Endmyopia Wiki - User contributions [en]

Severe myopia

2023-03-02T04:27:09Z

Snax: Undo revision 17007 by Snax (talk)

Minus eight diopters? Minus ten? Worse? No doubt you have been on the receiving end of a long series of ever stronger prescriptions from your optometrist or eye doctor. As a severe myope, you probably also spent much time with your nose in books or too close to a screen, landing you on the extreme end of the myopia spectrum.

Basically, your eyeballs are now egg-shaped. Stop being a stupid egg head. Grow some balls. Reverse direction. Do the EndMyopia program.

With severe myopia, there are some complications to be mindful of. This page explains them and provides you with guidance.

==Retinal detachment==
As your eyeballs elongate with increasing myopia, the retina—which is the light-sensing membrane at the back of the eye—becomes more tensioned. For severe myopes, the risk of retinal detachment is therefore markedly elevated[https://en.wikipedia.org/wiki/Retinal_detachment]. All the more reason to reverse direction.

Learn to recognize the symptoms[https://www.nhs.uk/conditions/detached-retina-retinal-detachment/]: when retinal detachment does happen, fast intervention and treatment can rescue you from losing sight in an eye.

==Avoid heavy glasses==
The front of minus lenses is flatter than the back, which is curved more strongly. In the center, minus lenses are typically only about 1.5mm thick (thinner would make the lenses too fragile), but moving away from the center (optical axis) the glass becomes thicker. The more minus the diopters, the larger the difference in curvature between the front and back surface of the lens, and the thicker the edge. You can determine how thick the lenses will get if you know all the parameters using [https://opticampus.opti.vision/tools/thickness.php this handy thickness calculator].

When choosing a normal frame with regular diameter lenses, you will end up with very thick lens edges and hence uncomfortably heavy glasses that easily slide off your nose and look ugly from the side. What to do?

===Choose frames with small-diameter lenses===
The smaller the diameter of the lenses once they are cut to fit the frame, the thinner the edges and lower the weight. Such frames are not considered very fashionable, and hence can be hard to find. But with severe myopia, the aesthetic and weight inconvenience of very thick edges make frames with small-diameter lenses very desirable.

Note though that small-diameter lenses clip your field of view.

===Opt for lenses with a high refractive index===
The higher the [https://en.wikipedia.org/wiki/Refractive_index refractive index] (''n''), the smaller the difference in front-back curvature needs to be for a lens to reach a given minus strength. Opting for high-''n'' glass therefore reduces the thickness of the lens edges and thereby significantly lowers the volume of the glass in the lens. This reduces weight, but less so than the volume reduction because the high refractive index is achieved by admixing lead in the glass[https://en.wikipedia.org/wiki/Lead_glass]: leaded glass weighs more per unit volume.

There are disadvantages:
* Cost: Zeiss goes up to ''n''=1.9, but these lenses can cost around $300 each at an optometrist.
* High refractive index lenses are subject to much stronger reflections at the lens/air interfaces. You really need [https://en.wikipedia.org/wiki/Anti-reflective_coating anti-reflective coatings], but these do not reduce reflections as much as they do for lower ''n'' lenses.
* [https://en.wikipedia.org/wiki/Chromatic_aberration Chromatic aberration] is worse since high-index glass or plastic has significantly more [https://en.wikipedia.org/wiki/Dispersion_(optics) dispersion] than regular glass. This is particularly noticeable when looking off to the side through the lenses, close to their edges, at a multi-color target such as an RGB LED.
When you have found a frame with very small diameter lenses, going for ''n''=1.7 or ''n''=1.8 might be good enough to keep the weight down and the edges thin. But the larger the lens diameter—and of course the stronger the lenses—the more necessary it becomes to keep the weight down and edge thickness under control by paying for the highest-''n'' lenses you can get.

===For a large field of view, choose plastic lenses and thick rims===
The density of plastic lenses is a few times lower than that of glass lenses. Hence, high-strength plastic lenses with a regular diameter and thus good field of view can still be reasonably light. But the refractive index of plastic lenses goes up to only 1.6 or 1.7 so that plastic lenses will have thicker edges than can be achieved with glass. These thick edges can be masked by choosing a frame with thick rims.<ref name="Jan">https://community.endmyopia.org/t/high-myope-says-hi/18100/42</ref>
===Pick frames with a well-matching pupillary distance===
Lenses are cut to fit the frame such that their optical axis (the thinnest part of a minus lens) sits right in front of the pupil of each of your eyes when looking straight ahead. If the frame perfectly matches your [[Pupillary Distance|pupillary distance]], the optical axis of the lenses will be right in the middle between the rims of the frame. This minimizes the thickness of the edges, and hence weight.

===Prefer round or oval frames===
With the optical axes of your eyes nicely centered in a frame, round frames result in a constant thickness of the lens edge since all of the edge is at the same distance from the optical axis. This means that round lenses minimize thickness and hence weight for a given field of view.

You probably want a bit more field of view horizontally than vertically, which makes oval frames a good compromise at the cost of thicker edges on the left and right side of the lenses. Avoid rectangular frames since the corners of the rectangles will be relatively far from the optical axis, making the lens edges there unnecessarily thick, ugly, and heavy.

==View compression and accounting for vertex distance==
Strong minus glasses significantly compress objects in your field of view such that they appear smaller. The closer the lenses are to your eyeballs, the less compression happens. At the same time, the angular coverage of the lens increases so that you have a larger field of view. Try it: move your minus glasses away from and back towards your eyeballs, and the view compression effect will be apparent.

When the lenses sit on your eyeballs, view compression is absent and the field of view is not clipped. This is the case when you wear contact lenses. For glasses you can get these benefits to some degree by choosing a frame with really small diameter lenses and adjusting the nose pads and ear hooks to position the lenses closer to your eyeballs than you would be able to with larger diameter frames: these won't fit between your eyebrow ridge and cheek bones. The practical limit on how deep you can place small-diameter lenses is reached when your eye lashes brush against the lenses.

As a severe myope, you probably learned that pushing your glasses up your nose a bit can bring distant objects into better focus. This is because moving a minus lens closer to your eyeball increases its effective strength. Read the page on [[vertex distance]] to learn the details. For high-strength minus lenses, this results in a significant vertex distance correction that you must take into account when doing the End Myopia program. The vertex distance can change markedly depending on the design and adjustment of your frames.

===Simplifying accounting for vertex distance===
By picking the same frame when buying new glasses, the vertex distance will not change. This makes it easier to compare the strengths of successive pairs of glasses. When the frame comes in different colors, you can cycle through the colors to prevent confusing the old glasses for the new ones.<ref name="Jan"/>

Severe myopia

2023-03-02T04:26:24Z

Snax: Reverted edits by NottNott (talk) to last revision by Candycrusher42

Minus eight diopters? Minus ten? Worse? No doubt you have been on the receiving end of a long series of ever stronger prescriptions from your optometrist or eye doctor. As a severe myope, you probably also spent much time with your nose in books or too close to a screen, landing you on the extreme end of the myopia spectrum.

Basically, your eyeballs are now egg-shaped. Stop being a stupid egg head. Grow some balls. Reverse direction. Do the End Myopia program.

With severe myopia, there are some complications to be mindful of. This page explains them and provides you with guidance.

==Retinal detachment==
As your eyeballs elongate with increasing myopia, the retina—which is the light-sensing membrane at the back of the eye—becomes more tensioned. For severe myopes, the risk of retinal detachment is therefore markedly elevated[https://en.wikipedia.org/wiki/Retinal_detachment]. All the more reason to reverse direction.

Learn to recognize the symptoms[https://www.nhs.uk/conditions/detached-retina-retinal-detachment/]: when retinal detachment does happen, fast intervention and treatment can rescue you from losing sight in an eye.

==Avoid heavy glasses==
The front of minus lenses is flatter than the back, which is curved more strongly. In the center, minus lenses are typically only about 1.5mm thick (thinner would make the lenses too fragile), but moving away from the center (optical axis) the glass becomes thicker. The more minus the diopters, the larger the difference in curvature between the front and back surface of the lens, and the thicker the edge. You can determine how thick the lenses will get if you know all the parameters using [https://opticampus.opti.vision/tools/thickness.php this handy thickness calculator].

When choosing a normal frame with regular diameter lenses, you will end up with very thick lens edges and hence uncomfortably heavy glasses that easily slide off your nose and look ugly from the side. What to do?

===Choose frames with small-diameter lenses===
The smaller the diameter of the lenses once they are cut to fit the frame, the thinner the edges and lower the weight. Such frames are not considered very fashionable, and hence can be hard to find. But with severe myopia, the aesthetic and weight inconvenience of very thick edges make frames with small-diameter lenses very desirable.

Note though that small-diameter lenses clip your field of view.

===Opt for lenses with a high refractive index===
The higher the [https://en.wikipedia.org/wiki/Refractive_index refractive index] (''n''), the smaller the difference in front-back curvature needs to be for a lens to reach a given minus strength. Opting for high-''n'' glass therefore reduces the thickness of the lens edges and thereby significantly lowers the volume of the glass in the lens. This reduces weight, but less so than the volume reduction because the high refractive index is achieved by admixing lead in the glass[https://en.wikipedia.org/wiki/Lead_glass]: leaded glass weighs more per unit volume.

There are disadvantages:
* Cost: Zeiss goes up to ''n''=1.9, but these lenses can cost around $300 each at an optometrist.
* High refractive index lenses are subject to much stronger reflections at the lens/air interfaces. You really need [https://en.wikipedia.org/wiki/Anti-reflective_coating anti-reflective coatings], but these do not reduce reflections as much as they do for lower ''n'' lenses.
* [https://en.wikipedia.org/wiki/Chromatic_aberration Chromatic aberration] is worse since high-index glass or plastic has significantly more [https://en.wikipedia.org/wiki/Dispersion_(optics) dispersion] than regular glass. This is particularly noticeable when looking off to the side through the lenses, close to their edges, at a multi-color target such as an RGB LED.
When you have found a frame with very small diameter lenses, going for ''n''=1.7 or ''n''=1.8 might be good enough to keep the weight down and the edges thin. But the larger the lens diameter—and of course the stronger the lenses—the more necessary it becomes to keep the weight down and edge thickness under control by paying for the highest-''n'' lenses you can get.

===For a large field of view, choose plastic lenses and thick rims===
The density of plastic lenses is a few times lower than that of glass lenses. Hence, high-strength plastic lenses with a regular diameter and thus good field of view can still be reasonably light. But the refractive index of plastic lenses goes up to only 1.6 or 1.7 so that plastic lenses will have thicker edges than can be achieved with glass. These thick edges can be masked by choosing a frame with thick rims.<ref name="Jan">https://community.endmyopia.org/t/high-myope-says-hi/18100/42</ref>
===Pick frames with a well-matching pupillary distance===
Lenses are cut to fit the frame such that their optical axis (the thinnest part of a minus lens) sits right in front of the pupil of each of your eyes when looking straight ahead. If the frame perfectly matches your [[Pupillary Distance|pupillary distance]], the optical axis of the lenses will be right in the middle between the rims of the frame. This minimizes the thickness of the edges, and hence weight.

===Prefer round or oval frames===
With the optical axes of your eyes nicely centered in a frame, round frames result in a constant thickness of the lens edge since all of the edge is at the same distance from the optical axis. This means that round lenses minimize thickness and hence weight for a given field of view.

You probably want a bit more field of view horizontally than vertically, which makes oval frames a good compromise at the cost of thicker edges on the left and right side of the lenses. Avoid rectangular frames since the corners of the rectangles will be relatively far from the optical axis, making the lens edges there unnecessarily thick, ugly, and heavy.

==View compression and accounting for vertex distance==
Strong minus glasses significantly compress objects in your field of view such that they appear smaller. The closer the lenses are to your eyeballs, the less compression happens. At the same time, the angular coverage of the lens increases so that you have a larger field of view. Try it: move your minus glasses away from and back towards your eyeballs, and the view compression effect will be apparent.

When the lenses sit on your eyeballs, view compression is absent and the field of view is not clipped. This is the case when you wear contact lenses. For glasses you can get these benefits to some degree by choosing a frame with really small diameter lenses and adjusting the nose pads and ear hooks to position the lenses closer to your eyeballs than you would be able to with larger diameter frames: these won't fit between your eyebrow ridge and cheek bones. The practical limit on how deep you can place small-diameter lenses is reached when your eye lashes brush against the lenses.

As a severe myope, you probably learned that pushing your glasses up your nose a bit can bring distant objects into better focus. This is because moving a minus lens closer to your eyeball increases its effective strength. Read the page on [[vertex distance]] to learn the details. For high-strength minus lenses, this results in a significant vertex distance correction that you must take into account when doing the End Myopia program. The vertex distance can change markedly depending on the design and adjustment of your frames.

===Simplifying accounting for vertex distance===
By picking the same frame when buying new glasses, the vertex distance will not change. This makes it easier to compare the strengths of successive pairs of glasses. When the frame comes in different colors, you can cycle through the colors to prevent confusing the old glasses for the new ones.<ref name="Jan"/>

Eye strain

2023-03-02T04:02:20Z

Snax: /* Distance Vision Strain */

'''Eye strain''', or '''asthenopia''', is fatigue of the ciliary muscles and extraocular muscles. Eye strain does not cause [[myopia]], but it can lead to [[pseudomyopia]]. Eye strain can lead to discomfort, including soreness and redness. As a rule the goal of [[EndMyopia]] is to use stimulus without causing unnecessary strain.

==The over-worked muscles==
The ciliary muscles control focus by changing the shape of the lens. Looking at near objects for extended periods of time strains the ciliary muscle, leading to a [[ciliary spasm]]. This muscle is most relaxed when looking far in the distance.

Extraocular muscles control the movement of the eye and the eyelid. These muscles may tighten during intense visual work or when the body perceives a threat. When tightened, a person may appear to be scowling or squinting. Closing the eyes and massaging around the eye can temporarily relax these muscles, but they will quickly tighten again if the core problem is not addressed with better habits. In addition to causing discomfort, strained extraocular muscles will result in a wrinkly, unpleasant facial expression.

==Causes and solutions==
[[Blur]] from uncorrected vision, or severely under corrected vision, causes eye strain. This problem is solved by wearing the [[differential]] or [[normalized]] lenses that are most appropriate for the situation and distance. Good ambient lighting will also go a long way to help avoid eye strain. More light means better vision, and natural light is the best light.

Staring at a computer monitor or other electronic screen for extended periods of time may cause eye strain under certain conditions:
* '''The screen contrasts with the environment'''. The color temperature and brightness of the screen should be adjusted to match the surrounding environment. Or, the lighting in the room may need to be adjusted to better match the screen. Having the lights off in the room while staring at a screen is never a good idea.
* '''The screen is too close to eyes'''. The screen should be at least an arm's length away from the eyes. With tiny phone screens, this is impractical; the bad habit of doing everything on the phone should be replaced with a good habit of doing as much as possible on a desktop or laptop computer at a healthy distance from the eyes. If you use a smartphone, consider replacing it with a feature phone.
* '''The staring is being done without reasonable breaks'''. At the very least, the eyes should be given a short break every 20 minutes and a long break every 60 minutes.
* '''The screen is low-quality or uses old technology'''. The old CRT technology is rarely used now, but be aware that its inherent flicker strains the eyes. The human eye certainly struggles when viewing light that flickers on and off 60 times per second! Unfortunately, even the current display technology, LCD, can flicker. Low-quality LCDs use PWM dimming, where the backlight is switched on and off hundreds of times per second. High-quality LCDs are designed with DC dimming, where the light is constant.

==Distance Vision Strain==
Some participants report feeling strain after long sessions of distance active focus.
One suggestion for handling distance strain is to balance both near and far accommodation, which is referred sometimes as "dynamic vision" activity. [https://www.youtube.com/watch?v=GM59lsIsl4M]
Different theories which are still in contention were proposed to describe the mechanism of accommodation. Some of those theories are:

'''Helmholtz theory of accommodation (1855)'''– This theory is also called the capsular theory of accommodation . Helmholtz theorized that when the eyes are viewing a distant object, the ciliary muscle relaxes and the zonular fibers between the ciliary body 1 and the equator of the lens stay flattened but when the object of focus is close, the ciliary muscles contract and the zonular fibers loosen. In the Helmholtz theory, the lens equator slides away from the sclera during accommodation and closer to the sclera when accommodation ends. In this theory, the zonular fibers are relaxed during accommodation and the zonular fibers are under tension when there is no accommodation reflex.

'''Schacher theory of accommodation (2006)'''- This theory states that when the lens is in focus, there is increased tension on the lens through the equatorial zonular fibers and when there is contraction of the ciliary muscle, the zonular fibers located equatorially increase their tensile strength. This results in the steepness of the central surface of the lens, an increase in thickness of the lens and a flattening of the lens edges. As the tension on the equatorial zonular fibers increase during accommodation, the anterior and posterior zonular fibers relax. The anterior and posterior zonular fibers serve as passive support structures for the lens, but the equatorial zonular fibers determines the refractive power of the lens.

Possibly related to: Theory of Reciprocal Zonular Action:
https://www.youtube.com/watch?v=1yIpyitm6eE

'''Catenary theory of accommodation (1970)'''– This theory is also called the Coleman theory of accommodation. It states that the lens and the zonula fibers form a diaphragm, which is held in a catenary (a curve formed by a wire, rope, or chain hanging freely from two points that are not in the same vertical line) shape due to the difference in pressure between the aqueous and vitreous bodies of the lens. A change in diameter of the ciliary body results in a change of the catenary shape. It means there is a continuous pressure difference on the lens. The strength of this pressure difference is approximately 2.3 cm of water column, with major changes occurring during the initial seconds of the accommodation phase. The anterior capsule and the zonular fibers form hammock shaped surface that is duplicable but depends on the diameter of the ciliary body. The ciliary body however makes a shape like the pillars of a suspension bridge, but does not need to support the force around the equator to flatten the lens.

[https://community.endmyopia.org/t/distance-vision-strain/17674 forum discussion on distance strain]

==References==
{{reflist}}

[[Category:Articles]]
[[Category:Eye conditions]]

Night vision

2023-02-19T06:37:35Z

Snax: Incorporate suggestions from forum regarding using previous normalized

Night vision is your ability to see in poor lighting conditions. Your color vision isn't very good at detecting low light levels, as the light dims your [[visual cortex]] depends more and more on your black and white vision and ignores the color input. You have fewer black and white detectors than color detectors, so you have less [[visual acuity]] at the same [[refraction]]. You may need to wear [[Full correction]] instead of [[Normalized]] lenses in poor light.

===Previous Normalized For Low Light Conditions===
Re: [https://community.endmyopia.org/t/break-plateaus-with-deload-week/19771 Forum: Break Plateaus with Deload Week?] and [https://community.endmyopia.org/t/break-plateaus-with-deload-week/19771/8 jakey's response]

While EM recommends ideally using 2 glasses (differentials and normalized) for both simplicity and consistency reasons, a repeated recommendation is to use previous normalized when low light conditions are more straining for current normalized. The conditions vary based on individual strain and level of under-correction, but in the thread some ideas were given for how to use extra diopters in low light conditions:

* Previous normalized is preferred for a boost in clarity. Others do find extra diopters helpful, but it's possible that need for additional diopter increments is a warning sign that excessive under-correction is happening. Even so in the latter case, use the diopters you need to operate safely in low light conditions.
* Ideally without ratio changes.
* Only in low light, only in short bursts.
* 10 minutes of extra clarity, in an otherwise challenging condition where you’re most likely to have lost clarity.
* It’s a noticeable increase, you get that dose you’re looking for of ‘reference acuity’. At the same time you’re minimizing the risk of sliding backwards if you were to use previous normalized in good lighting conditions and over longer periods.

Ideally differentials do not need to be adjusted for low light conditions, since distance and lighting is both consistent or easily tweaked.

===Vitamin A===
Vitamin A might help nighttime vision.<ref>[https://www.ebmconsult.com/articles/Vitamin-A-eye-vision-mechanism The Mechanism for Vitamin A Improvements in Night Vision]</ref>

==See Also==

* [https://endmyopia.org/why-vision-is-worse-at-night-and-on-cloudy-days-too/ Why Vision Is Worse At Night (and on cloudy days, too)]
* [https://www.arizonaretinalspecialists.com/blog/7-ways-improve-night-vision/ 7 Ways to Improve Night Vision] (This is not Jake-specific advice)

==References==
{{Reflist}}

[[Category:Articles]]

Close-up

2023-02-10T03:59:09Z

Snax: /* Videos */

Close up work is doing any vision task at arm's length or less for an extended period of time. This includes reading, phone time, computers, needlework, and many others.

When doing close up work, wear your [[differentials]] (if you need them) and follow the [[3 hour rule]] or the [[20-20-20 rule]].
==Videos==

{{#ev:youtube|E_STOn8NjzM}}

{{#ev:youtube|g0TCu_Yi1LE}}

==See Also==
*[[convergence]]
* [[Distance_vision]]

==References==
{{reflist}}

[[Category:Articles]]

Differentials

2023-02-07T19:13:38Z

Snax: added article to Differentials page: Pro Topic: Managing Your Maximum Diopter Gap

[[File:Microsoft Cloud Event Dublin, upclose with graphs.jpg|thumb|Without ''differentials'', you're on the path to ever increasing prescriptions and will get nowhere with vision improvement :(]]
'''Differentials''' ([[EM:JARGON|jargon]]), (''office glasses,'' ''close up'', ''computer use'' or ''diffs'') are reduced strength glasses or lenses for [[close-up|close up activity]]. They have a lower correction than your [[normalized]] lenses, the difference between them being usually between 1 and 2 [[diopters]].<ref>{{cite jake|https://endmyopia.org/faq-items/what-is-the-differential-prescription/|What is the differential prescription?}}</ref><ref name=ChooseReduction>{{cite jake|https://endmyopia.org/choose-reduced-glasses-prescription-differential-close-friendly-glasses/|How To Choose A Reduced Glasses Prescription (Differential / Close-Up Friendly Glasses)}}</ref> These are increasingly available under the name "office glasses" in some parts of Europe (per discord chat comment).

==Low Myopia==
People with myopia of -2 D to -1.5 D and lower do not typically need to wear differentials (because with -2 D your distance till blur should be around 50 cm, and with -1.5 D 67 cm, far enough to see your screen with sufficient clarity). The exception is that if you have more than 1 diopter of cylinder correction you will likely need differentials to help manage directional blur. In this event you likely can reduce the cylinder correction by between .25 and .75 D and pair it with a reduction of up to 1.25 D in spherical strength for either little or no spherical (plano) correction.

=== Last Diopter ===
Below -1 D, unless your close-up distance is around 100cm, you might consider using [[plus lenses]] as a differential. EndMyopia used to specify that they be used for low myopia, but they now consider it is a last resort.

==First Differentials==
The first differentials are typically 1.25 - 1.5 D weaker than your [[measurement]] for full distance vision. If you have -0.25 D of cylinder, you have the option of dropping that. If you have -0.5 to -0.75 D of cylinder, you have the option of dropping that and having the sphere only 1 - 1.25 D weaker.

See [[Lens#How to use Contacts with EM|How to use Contacts with EM]] if you wear contacts.

==Adjusting Differentials==
Ideally your differentials give you a small amount of blur at your daily near work. The nature of your work, the distance to your work, and your [[refractive state]] and [[cylinder]] dependence are all factors in choosing your differentials. The ideal distance for near work is not closer than 50 cm. You may get your first differentials and discover you have a headache and you really shouldn't have dropped cylinder. You may find that your work is pretty close or really far and you need to adjust the strength up or down. You may find that you really need detailed vision to do your work and you'll settle for slowing progression with your differentials and do your blur challenge for improvement in your off hours. This is the first place in the program where you really need to start understanding what you're tinkering with and make personalized diopter specific choices.

==Why are differentials worn?==
The primary stimulus for [[axial elongation]] of the eyeball is [[hyperopic defocus]], which occurs when someone:
* is engaged in close-up activity
* wears more correction than needed when seeing the object that is close up.

Differentials allow the wearer to wear ''just what they need to'', to see up close. This removes the stimulus of hyperopic defocus and stops eyes from getting more myopic. In a sense, it's a [[quick fix]]. {{wink}}

It's fairly easy to stop [[lens-induced myopia]] from progressing by just wearing differentials. The axial length of the eye does not randomly change by itself; it only changes in response to [[stimulus]].

Another reason to wear differentials is to avoid [[convergence]] issues. When viewing in close proximity the position of your eyes needs to compensate by turning in, particularly when you are looking nearer than 50 cm. Doing this for long periods of time on a regular bases is likely to cause issues. Such issues are easily avoided by wearing differential correction to accommodate a larger distance.

== Habits ==
It is useful to apply the [[3 hour rule]]  when engaging in close up (near) work.

Always be mindful to be in a good ergonomic position. Leaning in is a common issue and is something you need to be mindful to avoid.

Good ambient lighting is important because your eyes can not see as far or as well in low lighting. Natural light is best but supplement as needed.

== When are differentials worn ==
Standard EM advice is to wear differentials when looking at static focal planes (e.g. 2D planes like screens, books) at fixed distances for extended periods of time. The main activities EM warns against include screen work, media consumption, and checking phone notifications. It is okay to wear normalized in other contexts, such as when eating a meal, or looking at your conversation partners. It is also permitted to wear differentials in other close-up contexts based on personal preference, but there is no need to overdo normalized/differential glasses changes. (for example, there is no need to swap to differentials whenever someone walks up to you for a conversation)

To determine if a close up activity is hurting your vision with the glasses you are using (differentials or normalized), it helps to have a point of comparison (like a line on a snellen chart), and to compare against that reference point before and after the activity in question.

''' Example scenarios for differentials '''

Read a book with differentials. Use your computer with differentials.

Wear your differential glasses any time you are doing close work. If you have to get up to go to the bathroom, switch back to your normalized glasses. You get used to it pretty fast. "What if I just need to look out my window for like a minute?" CHANGE YOUR GLASSES. If you are asking yourself "should I switch to normalized glasses to look outside the [[blur horizon]] of my differential glasses?" the answer is always YES.

But for convenience, you might choose a threshold time and not change your glasses if it would be worn for less than that threshold. As an example, see the [[20-20-20 rule]] page.

'''What is "close" work?'''

Norms minus diffs = the number of diopters you need to convert to find this answer. For example, if your normalized glasses are -5 and your differential glasses are -3.5, then you need to convert -1.5. You should be able to see 66.67cm with -1.50 myopia! That's about 26.24 inches, or a little more than 2 feet.

== See also ==

* [[Explainer:The_Eyesight_Improvement_Equation#Good_close-up_habits|The Eyesight Improvement Equation: Good close-up habits]]
* [[Normalized#When_do_I_wear_normalized|When do I wear normalized]]
* [[Guide:Reducing differentials]]
* [[Guide:Measuring with differentials]]
* [https://www.youtube.com/watch?v=7HM5oOAexww differentials: a video]
* [https://www.youtube.com/watch?v=EWJxPpSksag Q&A: Reading Books With Differentials - No Blur Horizon?]
* [https://endmyopia.org/pro-topic-managing-your-maximum-diopter-gap/ Pro Topic: Managing Your Maximum Diopter Gap]

==References==
{{reflist}}

[[Category:Articles]]
[[Category:Lens selections]]

Negative reviews

2023-01-29T22:10:11Z

Snax:

* [https://www.quora.com/Is-endmymyopia-orgs-information-true-Can-myopia-really-be-reversible/answer/Por-Yong-Ming?ch=15&oid=249656063&share=a3a5dd74&srid=kGuQA&target_type=answer&fbclid=IwAR2757OkDXD8mHyd2a7Thcv_1-9WUIKs1ORyESfe6CfCYvfn1XFjiP04Kqs -10 D myopic Eye-surgeon's review of EndMyopia]
* "Sometimes it was unbearable and this was the time when i called my doctor. I didnt spoke to him about this method is just told my problems. He dilated my pupils and checked my retina. During the examination he just literaly said: [https://www.reddit.com/r/myopia/comments/viq8ln/the_truth_about_endmyopia_and_jake_steiner_my/ „Man what happened to your eyes.”] And what was the problem? I got lattice degneration and holes all over my retina and i got a VERY BIG TEAR in my right eye in which i felt pressure…."
* [https://old.reddit.com/r/myopia/comments/viq8ln/the_truth_about_endmyopia_and_jake_steiner_my/idt7217/?context=3 Ah .Man I thought I was only suffering this .Man I got flashes in peripheral vision in both eye after doing active foucs for 3 month.I didn't had any floaters before I do active foucs.Now I have flashes in my peripheral vision.I went to optometrist he saids I have lots of eye floaters and saw 2 lesion hole.He refered me to retina specialist.Iuckily I didn't have to laser.He Explained me about warning signs like curtain across.And he also asked me about migraine. because I also have flashes in both eye.i have -5.5 prescription in both eyes.its been 6 month .I was lucky because I didn't had big lesion holes]

Negative reviews

2023-01-29T21:42:54Z

Snax:

* "Sometimes it was unbearable and this was the time when i called my doctor. I didnt spoke to him about this method is just told my problems. He dilated my pupils and checked my retina. During the examination he just literaly said: [https://www.reddit.com/r/myopia/comments/viq8ln/the_truth_about_endmyopia_and_jake_steiner_my/ „Man what happened to your eyes.”] And what was the problem? I got lattice degneration and holes all over my retina and i got a VERY BIG TEAR in my right eye in which i felt pressure…."

* [https://old.reddit.com/r/myopia/comments/viq8ln/the_truth_about_endmyopia_and_jake_steiner_my/idt7217/?context=3 Ah .Man I thought I was only suffering this .Man I got flashes in peripheral vision in both eye after doing active foucs for 3 month.I didn't had any floaters before I do active foucs.Now I have flashes in my peripheral vision.I went to optometrist he saids I have lots of eye floaters and saw 2 lesion hole.He refered me to retina specialist.Iuckily I didn't have to laser.He Explained me about warning signs like curtain across.And he also asked me about migraine. because I also have flashes in both eye.i have -5.5 prescription in both eyes.its been 6 month .I was lucky because I didn't had big lesion holes]

Negative reviews

2023-01-29T21:42:32Z

Snax:

* "Sometimes it was unbearable and this was the time when i called my doctor. I didnt spoke to him about this method is just told my problems. He dilated my pupils and checked my retina. During the examination he just literaly said: [https://www.reddit.com/r/myopia/comments/viq8ln/the_truth_about_endmyopia_and_jake_steiner_my/ „Man what happened to your eyes.”] And what was the problem? I got lattice degneration and holes all over my retina and i got a VERY BIG TEAR in my right eye in which i felt pressure…."

* [https://old.reddit.com/r/myopia/comments/viq8ln/the_truth_about_endmyopia_and_jake_steiner_my/idt7217/?context=3 Ah .Man I thought I was only suffering this .Man I got flashes in peripheral vision in both eye after doing active foucs for 3 month.I didn't had any floaters before I do active foucs.Now I have flashes in my peripheral vision.I went to optometrist he saids I have lots of eye floaters and saw 2 lesion hole.He refered me to retina specialist.Iuckily I didn't have to laser.He

Explained me about warning signs like curtain across.And he also asked me about migraine. because I also have flashes in both eye.i have -5.5 prescription in both eyes.its been 6 month .I was lucky because I didn't had big lesion holes]

Peak Prescription

2023-01-29T06:43:49Z

Snax:

Also known as "Peak Diopters".

Use of Peak Prescription is considered an advanced troubleshooting technique, so when it doubt, stick to only having two glasses, normalized and differentials.

A Peak Prescription is [https://endmyopia.org/alex-unlock-one-diopter-margin-vision/ your next] [[Normalized]]. Alternatively, you can use old differentials (with their stronger diopters than current differentials) as a peak prescription.

It could be [https://endmyopia.org/what-you-missed-the-peak-prescription/ used when the Normalized has too much correction], but be careful not to use too many focal planes.

It is useful for [https://endmyopia.org/how-to-getting-the-most-out-of-your-peak-prescription/ measuring close-up strain].

It is also useful for [https://endmyopia.org/alex-unlock-one-diopter-margin-vision/ this exercise].

The EM blog has an example where [https://endmyopia.org/part-2-improvements/ the peak prescription (and therefore next normalized) is -8, which is 1.5 D under the current normalized of -9].

The EM forums also has an example where [https://community.endmyopia.org/t/my-journey-from-4-25-halmadavid/5080/739 a previous differential can be used as a fallback from a new differential], in case it is challenging to get used to a new differential reduction.

Only start using peak diopters when you are not getting stimulus from your current normalized, or if you are troubleshooting a plateau. When getting used to a reduction (whether current normalized, or next normalized), it is better to have only one pair of glasses you are getting acclimated to at a time,.

'''EM Protocol for Peak Prescription'''
* [Option A] Start days without glasses (zero diopter reset)
* [Option B] Start days with differentials (particularly if personal myopia level is too high to be comfortable for the start of the day)
* Switch to the peak diopters in peak conditions (like a brightly lit morning walk) for 30-120 minutes of an active focus promoting activity. Proceed to the next step of using normalized glasses earlier if you feel fatigue.
* Switch to your current normalized for the rest of the day.

Over time, move toward using peak prescription as the next normalized, as that pair of glasses becomes more comfortable to use.

Avoid introducing too many focal planes too early. Switching frequently between two unfamiliar reduction glasses has anecdotally stalled progress, so make sure current normalized adaptation is locked in before introducing peak diopters.

[https://endmyopia.org/another-get-past-plateau-post/]

[[Category:Articles]]
[[Category:Lens selections]]

Double vision

2023-01-27T06:39:42Z

Snax: /* See also */

'''Double Vision''', misaligned vision, or ghosting, is when your visual cortex perceives two images when there should be one.

[[File:Diplopia.jpg]]

This phenomenon usually occurs as an intermediate step in your vision improvement and is to be differentiated from [[Astigmatism]] ("Directional Blur"). Your vision biology is constantly adjusting to environmental stimulus, whereby different parts of your system respond at different rates. After clearing up [[Ciliary Spasm]] and after starting to improve the physical shape of your eyeball, your [[visual cortex]] already receives plenty of clear data. Our brains however were not built to handle artificial changes to the natural [[Focal Plane]]. This means that even when the image hitting your [[Retina]] is clear after reducing the strength of your glasses, your brain has to relearn how to create a single clear image out of this new data. This can take longer than resolving the refractive state of your eyeballs and manifests in multiple overlapping clear images of the same image.
This might be somewhat common as you start improving your eyesight - more ghosted images will begin to appear as your [[visual cortex]] is constantly learning to readjust to new signals.

If there is too much double vision, you might have to step up to clear it and avoid [[blur adaptation]].

Double Vision can be more pronounced once you are in the [[Low Myopia]] range, since every small change in your diopter strength then results in a larger shift of your [[Focal Plane]].

'''For help resolving double vision see the [[Guide:Resolving double vision]].'''

==Transient Astigmatism==
'''Transient astigmatism''' ([https://endmyopia.org/transient-astigmatism-reduced-diopters-now-got-astigmatism/ article], [https://www.youtube.com/watch?v=DxemH7AoMI8 video]) is double vision and measurable cylinder that occurs [[reduction|when you reduce]] spherical and is temporary, so you should stop reducing and wait for it to disappear plus a little bit extra time, and reduce less aggressively next time. It becomes more severe when you reduce too quickly<ref>"So people that push the reductions get this transient astigmatism symptom that’s kind of a pain." https://endmyopia.org/ruis-glasses-and-headaches-9-75-to-6-00-progress/</ref> or too much or too often.

Even though it's functionally the same as real [[astigmatism]] (although rapidly changing on axis and amount), do not get cylinder correction for it, to the maximum extent possible, since you're just transitioning between two spherical values. If you do, you would just put extra load on your visual cortex for no reason, slowing down your progress.

If it's too noticeable, you can step up spherical, but if it's not that bad ("if you don't notice it, or if you hardly ever notice it, or if it's really just something that the optometrist shows and you see a tiny little bit better"), it's also OK to leave it.

If you somehow created a very large amount of transient astigmatism, [https://endmyopia.org/plus-lens-therapy-read-this-before-trying/ such as this person who had up to 4.25 D of myopic defocus], you might consider adding some cylinder correction, but only as a last resort.

==What is the difference between astigmatism double vision and endmyopia double vision?==

[[Astigmatism]] refers to a condition that creates [[directional blur]], that when significant enough requires cylinder correction. [https://endmyopia.org/wp-content/uploads/2016/02/hd-astigmatic-blur-vs-myopic-blur.jpg This is what directional blur looks like.]

Double vision, there are many kinds of it. For example, astigmatism might present itself as double vision but astigmatic blur doesn't have to have DV. But there can be double vision that's not caused by astigmatism.

There's no such thing as EM DV. But there is something Jake refers to called ''transient astigmatism''. Which can come in various forms. Double vision, multiple transparent copies, ghosting, and other things of the sort.

When he talks about transient astigmatism he is referring to a transition period that exists while you are making gains. A period where your myopia has improved to the point where things are clear in terms of myopic blur, but you still have some disturbances in your vision.

There's really a lot of overlap honestly. Don't take the definitions too seriously. They're just ideas to help you look at what you're actually seeing. Because often people see things, but do not pay attention to how exactly these things look to them.

The goal is to get familiar with the nuances of [[blur]]. Because there are many different ways blur can look.

==See also==

* [[Blur]] (blur is different than double vision)<ref>https://endmyopia.org/the-giant-double-vision-thread/</ref><ref>https://endmyopia.org/reminder-tip-recognize-double-vision/</ref>
* https://www.youtube.com/watch?v=7qdJaPUUNRM

==References==
{{reflist}}

[[Category:Articles]]

EndMyopia Diopter Calculator

2023-01-26T07:04:57Z

Snax:

[[File:Diopter Calculator Android.jpg|right|400px]]
The Android app '''Diopter Calculator''' allows one to estimate centimeter measurements using a front facing phone camera to estimate distance to the selfie's nose.

[https://play.google.com/store/apps/details?id=org.endmyopia.calc Diopter Calculator on Google Play Store]

[https://github.com/denisk20/diopter-calc The code is open sourced here]

==The web tool==
The '''EndMyopia Diopter Calculator''' is an online tool used to calculate [[diopters]] from [[edge of blur]]. It can form a good starting point for where to reduce from.

{{bigger|[https://endmyopia.org/focal-calculator/calc.html Find the tool here]}}

{{bigger|[https://endmyopia.org/myopia-calculator-2/ More information about how to use the tool here]}}

[[File:EndMyopia Diopter Calculator.png|right|400px]]

=== See also ===
* [[Varakari's Vision Log Tool]]

EndMyopia Diopter Calculator

2023-01-26T07:02:57Z

Snax:

[[File:Diopter Calculator Android.jpg|right|400px]]
The Android app '''Diopter Calculator''' allows one to estimate centimeter measurements using a front facing phone camera to estimate distance to the selfie's nose.

{{bigger|[https://play.google.com/store/apps/details?id=org.endmyopia.calc Diopter Calculator on Google Play Store]}}

{{bigger|[https://github.com/denisk20/diopter-calc The code is open sourced here]}}

[[File:EndMyopia Diopter Calculator.png|right|400px]]
The '''EndMyopia Diopter Calculator''' is an online tool used to calculate [[diopters]] from [[edge of blur]]. It can form a good starting point for where to reduce from.

==The web tool==
{{bigger|[https://endmyopia.org/focal-calculator/calc.html Find the tool here]}}

{{bigger|[https://endmyopia.org/myopia-calculator-2/ More information about how to use the tool here]}}

=== See also ===
* [[Varakari's Vision Log Tool]]

File:Diopter Calculator Android.jpg

2023-01-26T07:02:32Z

Snax:

EndMyopia Diopter Calculator

2023-01-26T07:00:46Z

Snax:

[[File:Diopter Calculator Android.png|right|400px]]
The Android app '''Diopter Calculator''' allows one to estimate centimeter measurements using a front facing phone camera to estimate distance to the selfie's nose.

{{bigger|[https://play.google.com/store/apps/details?id=org.endmyopia.calc Diopter Calculator on Google Play Store]}}

{{bigger|[https://github.com/denisk20/diopter-calc The code is open sourced here]}}

[[File:EndMyopia Diopter Calculator.png|right|400px]]
The '''EndMyopia Diopter Calculator''' is an online tool used to calculate [[diopters]] from [[edge of blur]]. It can form a good starting point for where to reduce from.

==The web tool==
{{bigger|[https://endmyopia.org/focal-calculator/calc.html Find the tool here]}}

{{bigger|[https://endmyopia.org/myopia-calculator-2/ More information about how to use the tool here]}}

=== See also ===
* [[Varakari's Vision Log Tool]]

3 hour rule

2023-01-26T06:43:18Z

Snax:

The 3 hour rule is a suggestion to keep a balance between near work and time spent using distance vision and reduce [[eye strain]]. This can be an effective alternative to the [[20-20-20 rule]].

* After 3 hours of continuous close-up time, get an hour of continuous distance time.
* Do not exceed 3 hours of close-up time.
* Ideally for the break, get some distance vision with norms for 1 hour, to compensate for every 3 hour of close up.

If you do near work for 4 hours or more continuously, it is likely you will have ciliary spasm that is harder to resolve and it may be more difficult to make improvements.
==Videos==

{{#ev:youtube|kIuN9Jjxccg}}

Peak Prescription

2023-01-13T04:09:16Z

Snax:

Peak Prescription

2023-01-13T04:09:00Z

Snax:

Also known as "Peak Diopters".

Use of Peak Prescription is considered an advanced troubleshooting technique, so when it doubt, stick to only having two glasses, normalized and differentials.

A Peak Prescription is [https://endmyopia.org/alex-unlock-one-diopter-margin-vision/ your next] [[Normalized]]. Alternatively, you can use old differentials (with their stronger diopters than current differentials) as a peak prescription.

It could be [https://endmyopia.org/what-you-missed-the-peak-prescription/ used when the Normalized has too much correction], but be careful not to use too many focal planes.

It is useful for [https://endmyopia.org/how-to-getting-the-most-out-of-your-peak-prescription/ measuring close-up strain].

It is also useful for [https://endmyopia.org/alex-unlock-one-diopter-margin-vision/ this exercise].

The EM blog has an example where [https://endmyopia.org/part-2-improvements/ the peak prescription (and therefore next normalized) is -8, which is 1.5 D under the current normalized of -9].

The EM forums also has an example where [https://community.endmyopia.org/t/my-journey-from-4-25-halmadavid/5080/739?u=snax a previous differential can be used as a fallback from a new differential], in case it is challenging to get used to a new differential reduction.

Only start using peak diopters when you are not getting stimulus from your current normalized, or if you are troubleshooting a plateau. When getting used to a reduction (whether current normalized, or next normalized), it is better to have only one pair of glasses you are getting acclimated to at a time,.

'''EM Protocol for Peak Prescription'''
* [Option A] Start days without glasses (zero diopter reset)
* [Option B] Start days with differentials (particularly if personal myopia level is too high to be comfortable for the start of the day)
* Switch to the peak diopters in peak conditions (like a brightly lit morning walk) for 30-120 minutes of an active focus promoting activity. Proceed to the next step of using normalized glasses earlier if you feel fatigue.
* Switch to your current normalized for the rest of the day.

Over time, move toward using peak prescription as the next normalized, as that pair of glasses becomes more comfortable to use.

Avoid introducing too many focal planes too early. Switching frequently between two unfamiliar reduction glasses has anecdotally stalled progress, so make sure current normalized adaptation is locked in before introducing peak diopters.

[[Category:Articles]]
[[Category:Lens selections]]

Guide:Start your improvement here

2023-01-09T22:04:46Z

Snax: /* Future Steps - Reverse Your Myopia */

[[File:EMBoxLogoTransparent.png|right|200px]]
'''Welcome to [[EndMyopia]]''', the prime place on the internet for regaining your own natural eyesight and reversing your [[Myopia]].

'''EndMyopia isn't a simple program of steps. This page is just the entrance to the rabbit hole.''' Nobody here can tell you how well your eyes will react to a specific change, or what glasses are right for your eyes and your vision habits and your work requirements, we can just give you the tools to understand your own eyesight, what causes myopia progression and how to stop and reverse it.

==The Beginning Steps - Stop Myopia Progression==
# Measure your eyes - you can start with a professional refraction, but you should also learn to measure your own vision at home.
#* If your refraction is better than -10, the [[Measurement#cm_Measurement|cm measurement]] is easy to do and compare values. The cm measurement measures your myopia.
#* The [[Snellen chart]] measures all the combined factors of [[Visual acuity]] and is necessary for checking if your vision meets the legal requirements in your jurisdiction for driving.
#* Measuring your myopia and visual acuity regularly will tell you when the steps you are taking are working.
# Take breaks from near work (Follow the [[3 hour rule]] or the [[20-20-20 rule]] for starters)
# Don't wear glasses for near work if you don't need them.<ref>[https://endmyopia.org/day-57-myopia-progression-the-one-thing-you-have-to-stop-doing Myopia Progression: The One Thing You Have To Stop Doing]</ref>
# Get separate glasses for near work if you do need them. We call these [[Differentials]] if your doctor is willing to prescribe them, he may call them computer glasses or reading glasses.<ref>[https://endmyopia.org/day-67-differential-glasses-for-close-up-use Differential Glasses for CLOSE-UP Use]</ref>
# Give this a few weeks, you may be able to release [[Pseudomyopia]] with these steps alone, which will change your eye measurement that you will base your next pairs of glasses on.

==Time to Learn==
{{gif fixer|[[File:Cute cat with glasses and tie reading laptop.gif]]|right}}
Experience has shown many times that without adequate knowledge of the process, people are really unlikely to make any improvements in their eyesight. There is always more to learn about vision improvement, and you should not be afraid to spend significant amounts of time reading the resources already available to you. Arm yourself with knowledge to deal with any bumps in the road that come your way. The community won't answer your medical questions or diopter specific questions, take medical questions to your doctor, and do your own work to understand your specific diopter needs.
# Get the [[seven day free email guide]] - This is a must, if you ask a question in the community that's answered in this guide, your thread will quite possibly be closed by a moderator.
# Consult the [https://endmyopia.org/faqs/ Blog Frequently Asked Questions] and [[Frequently Asked Questions| Wiki Frequently Asked Questions]]
# Read the [{{em}} the blog]
## Hover over (with your mouse) “Blog and How-to’s” and check the “Eyesight How-To’s” and any other sections relevant to you.
## Search the blog. Do you know how to search the [https://endmyopia.org/ blog]? Hit the 🔍️ in the upper right corner and fill in the relevant search item there.
# Watch [[EndMyopia YouTube Channel]]
# Watch [[List:Community YouTubers]]
# Use the Wiki as a reference when you need an overview of a new topic.
# Read the [[Guide:How to ask for support]] then join the [[EndMyopia Forum]] and/or [[EndMyopia_Discord_Server | Discord]] Community.

==Future Steps - Reverse Your Myopia==

# Get slightly reduced glasses for other times when you don't need perfect vision. We call these [[normalized]]. They give a slight blur challenge at a distance. Because glasses are generally rounded off to the nearest quarter diopter, full strength lenses are likely to be slightly over prescribed even if your [[optometrist]] follows the best practices and procedures of his profession. A quarter diopter low would put your distance to blur at 4m, or about 13 feet, and allow your [[ciliary muscle]] to relax when viewing at that distance and beyond. <ref>[https://www.youtube.com/watch?v=LI9JphYXQ6A 20/50 Rule For Improving Eyesight]</ref>
# Find Active Focus, a way of getting your eyes to see slightly further than their normal distance to blur. [[Guide:How_to_find_Active_Focus|Guide: How to find Active Focus]] <ref>[https://endmyopia.org/active-focus-links/ There is a category of blog posts about Active Focus here.]</ref>
# When you're ready, do your first [[reduction]]<ref>[https://www.youtube.com/watch?v=zzrQb4pCFkQ Reduce Normalized Diopters]</ref>

== Putting it all together==

[https://endmyopia.org/wp-content/uploads/2021/12/one-page-cliff-notes-endmyopia.jpg The one page cliff notes]

==Keep Learning==
This page is just the entrance to the rabbit hole. Keep referring to the learning resources above even after you've made your first successful reductions.

You are likely to make mistakes along this journey: there is trial and error as you perfect the approach taken to improving vision. If at any time you have discomfort or disfunction in your new glasses, step back to the previous pair you were comfortable in. The basic ideas are really simple to understand, but there is a lot of nuance in how to apply them, and this can take time to understand fully.

==Beginner's Guide to Vision Improvement==
<youtube>XPIGDSY_xBs</youtube>

==Translations==
This guide has been translated to Polish. See [[EndMyopia Translated]]

==See also==
* [[Student content for new members]]
* [https://www.youtube.com/watch?v=xU6mJr16huk Video Version of Getting Started]
* [https://endmyopia.org/how-to-eyesight-improve-five-steps/ How To Improve Your Eyesight: Just 5 Steps]

[[Category:Guides]]

Guide:Not reducing too quickly

2023-01-03T03:55:00Z

Snax: /* Avoiding the too fast reduction trap */

The temptation of every student of EndMyopia is to reduce their correction faster or more than their measurements justify. Or in many cases to cause their measurements to justify a [[reduction]] they have not actually yet earned, by using [[active focus]] when measuring. [[Visual acuity]] is not intended to be a measurement of your ability to active focus. Your true myopia value doesn't change until your vision actually improves. The amount of correction you're wearing is arbitrary rather you are .25 diopters under corrected or 2 diopters. The only difference being rather the correction you are wearing provides good stimulus or excessive strain and risk of [[blur adaptation]].

==Avoiding the too fast reduction trap==
The best ways to avoid falling into the trap of reducing too quickly or too much is to be sure you are measuring objectively and as accurately as possible. Many things affect our vision and if you only take into account the measurements achieved with the ideal settings (ex. outside in full sun, first thing in the morning) you will always reduce faster and/or more than you should. By all means note these measurements but also get measurements that are in less ideal conditions (ex. artificial lighting at the end of the day). If you are taking your full range of vision into account you are much more likely to set your correction at a middle point, to provide good stimulus without excessive blur in most settings. It is usually <u>not</u> a good idea to reduce until you are consistently measuring 20/20 indoors for about 2 weeks.

Also note that different aspects of your vision tend to be affected at different rates, it is not unusual to have your [[snellen chart]] results change at a different time than your cm measurements. Often your distance landmark (provided you have a proper text reference) will be the last thing to improve, as it is well outside the diopter bubble. Additionally your eyes will improve at a different rate in relation to each other. This is known as [[ocular dominance]] and it is important to be sure both eyes are ready to reduce or you will be putting your non dominant eye at a disadvantage in the new correction and this may result in opening a [[diopter gap]] that can and should be avoided.

The point will come in your [[reduction]] when all of your measurements reflect your improvement consistently in both eyes and then you know it is time to reduce.

'''Face recognition test'''

Another indication that one has reduced too much is when recognizing faces becomes difficult in a social setting. It is a common experience to accidentally cheat at Snellen or cm measurements, while not being able to recognize a friend at a socially acceptable range is strong indicator for having reduced too much.

If you are unable to read signage, such as on the street or indoors, that is also another indication that you have reduced too much.

[https://endmyopia.org/qa-does-blur-stress-and-how-much-focus-is-too-much-focus/ Q&A: Does Blur = Stress? And How Much Focus Is Too Much Focus?]

==I already reduced==
If you already fell into the trap of reducing too quickly or too much, don't worry you are not alone. If you are still managing to improve, great! You got away with it this time; don't expect it to be a pattern though. More likely though you have stalled in progress and it is time to dial that correction up to where it belongs. Having a correction just .25 less than your full [[20/20 correction]] is the best way to provide good stimulus with resolvable blur that doesn't disrupt your day to day life. '''Going back up is not a step backwards''', once again your true myopia value is the same regardless of how under corrected you are. Increasing your correction gives your eyes the opportunity to achieve [[active focus]], without which you will not improve. Don't waste time and risk [[blur adaptation]] trying to "stick out" a correction that has too much blur, put that correction away (you will get back to it) and get into the right correction.

==See Also==

* [[Blur adaptation]]
* [[reduction | Reduction]]
* [[Guide:Reducing lens complexity | Reducing lens complexity]]
* [[Guide:Reducing_differentials | Reducing differentials]]
* [[Guide:Reducing normalized | Reducing normalized]]

==References==
What does Jake say about it? https://endmyopia.org/reducing-too-quickly-why-its-your-biggest-mistake/

More here: https://endmyopia.org/?s=reducing+too+quickly

[https://endmyopia.org/qa-can-reduce-1-2-diopter-get-moar-gains/ Can I Reduce More Diopters For More Gains?] (Spoiler, NO.)

Guide:Not reducing too quickly

2023-01-03T03:54:49Z

Snax: /* Avoiding the too fast reduction trap */

The temptation of every student of EndMyopia is to reduce their correction faster or more than their measurements justify. Or in many cases to cause their measurements to justify a [[reduction]] they have not actually yet earned, by using [[active focus]] when measuring. [[Visual acuity]] is not intended to be a measurement of your ability to active focus. Your true myopia value doesn't change until your vision actually improves. The amount of correction you're wearing is arbitrary rather you are .25 diopters under corrected or 2 diopters. The only difference being rather the correction you are wearing provides good stimulus or excessive strain and risk of [[blur adaptation]].

==Avoiding the too fast reduction trap==
The best ways to avoid falling into the trap of reducing too quickly or too much is to be sure you are measuring objectively and as accurately as possible. Many things affect our vision and if you only take into account the measurements achieved with the ideal settings (ex. outside in full sun, first thing in the morning) you will always reduce faster and/or more than you should. By all means note these measurements but also get measurements that are in less ideal conditions (ex. artificial lighting at the end of the day). If you are taking your full range of vision into account you are much more likely to set your correction at a middle point, to provide good stimulus without excessive blur in most settings. It is usually <u>not</u> a good idea to reduce until you are consistently measuring 20/20 indoors for about 2 weeks.

Also note that different aspects of your vision tend to be affected at different rates, it is not unusual to have your [[snellen chart]] results change at a different time than your cm measurements. Often your distance landmark (provided you have a proper text reference) will be the last thing to improve, as it is well outside the diopter bubble. Additionally your eyes will improve at a different rate in relation to each other. This is known as [[ocular dominance]] and it is important to be sure both eyes are ready to reduce or you will be putting your non dominant eye at a disadvantage in the new correction and this may result in opening a [[diopter gap]] that can and should be avoided.

The point will come in your [[reduction]] when all of your measurements reflect your improvement consistently in both eyes and then you know it is time to reduce.

'''Face recognition test'''
Another indication that one has reduced too much is when recognizing faces becomes difficult in a social setting. It is a common experience to accidentally cheat at Snellen or cm measurements, while not being able to recognize a friend at a socially acceptable range is strong indicator for having reduced too much.

If you are unable to read signage, such as on the street or indoors, that is also another indication that you have reduced too much.

[https://endmyopia.org/qa-does-blur-stress-and-how-much-focus-is-too-much-focus/ Q&A: Does Blur = Stress? And How Much Focus Is Too Much Focus?]

==I already reduced==
If you already fell into the trap of reducing too quickly or too much, don't worry you are not alone. If you are still managing to improve, great! You got away with it this time; don't expect it to be a pattern though. More likely though you have stalled in progress and it is time to dial that correction up to where it belongs. Having a correction just .25 less than your full [[20/20 correction]] is the best way to provide good stimulus with resolvable blur that doesn't disrupt your day to day life. '''Going back up is not a step backwards''', once again your true myopia value is the same regardless of how under corrected you are. Increasing your correction gives your eyes the opportunity to achieve [[active focus]], without which you will not improve. Don't waste time and risk [[blur adaptation]] trying to "stick out" a correction that has too much blur, put that correction away (you will get back to it) and get into the right correction.

==See Also==

* [[Blur adaptation]]
* [[reduction | Reduction]]
* [[Guide:Reducing lens complexity | Reducing lens complexity]]
* [[Guide:Reducing_differentials | Reducing differentials]]
* [[Guide:Reducing normalized | Reducing normalized]]

==References==
What does Jake say about it? https://endmyopia.org/reducing-too-quickly-why-its-your-biggest-mistake/

More here: https://endmyopia.org/?s=reducing+too+quickly

[https://endmyopia.org/qa-can-reduce-1-2-diopter-get-moar-gains/ Can I Reduce More Diopters For More Gains?] (Spoiler, NO.)

Guide:Reading glasses prescriptions

2023-01-03T03:46:50Z

Snax: /* Cylinder */

How do you read these complicated things!? Believe it or not, they're actually pretty simple to understand. First things first, remember myopia is not a medical condition, it is a refractive error. Therefore, your "prescription" is much more accurately referred to as vision [[correction]]. OD is oculus dextrus, or Latin for right eye. OS is oculus sinister, or Latin for left eye.

==Spherical==
{{main|Spherical}}
Spherical is the overall correction, in all directions. It is measured in [[diopters]]. A minus value means the lense is used correct [[myopia]] and a plus value means it is used to correct [[presbyopia]] and/or [[hyperopia]].

==Cylinder==
{{main|Cylinder}}
Cylinder is the additional correction in a specific direction of your eye. It is measured in [[diopters]]. Think of a straight line going across the surface of your eye at a certain degree. The degree this happens at is your [[axis]].

Cylinder correction means your eye has some level of [[astigmatism]].

Since cylinder correction is in addition to spherical correction, what the cylinder correction does depends on the spherical correction:
{| class="wikitable"
|+ Effect of including cylinder correction
! !! Minus Sphere !! Plus Sphere
|-
! Minus Cyl
| Increases myopia correction || Decreases presbyopia correction
|-
! Plus Cyl
| Decreases myopia correction || Increases presbyopia correction
|}

[https://www.youtube.com/watch?v=0AyE1BmKUh8 Explanation of positive vs. negative cyl correction]

==Axis==
{{main|Axis}}
Axis is the degree at which cylinder values are relevant. The correct cylinder value but the wrong axis value would make the correction pretty worthless! When reducing your correction, you should never ever change the axis, especially if you've had that value of axis for a long time.

If you don't have any cylinder correction, you will not have an axis value either.

==Prism==
{{main|Prism}}
Prism is very rare on a prescription. It is effectively is an imbalance between how your two eyes see. It has been described as permanent [[double vision]].

==Pupillary Distance==
{{main|Pupillary Distance}}
Pupillary Distance or PD, is the final set of numbers you need to be aware of. Most likely this is not listed on your "prescription" you will need to ask for it or measure it yourself.

[[Category:Guides]]

List:Measurement tools

2023-01-03T03:44:39Z

Snax:

The following is a list of tools created to measure vision improvement progression, usually in [[centimeters]].

==cm measurements==
* https://endmyopia.org/focal-calculator/calc.html
* [[Varakari's Vision Log Tool]]
* [https://play.google.com/store/apps/details?id=org.endmyopia.calc Diopter Calculator Android App]
https://wiki.endmyopia.org/wiki/Measurement

Differentials

2023-01-03T03:08:47Z

Snax: /* See also */

[[File:Microsoft Cloud Event Dublin, upclose with graphs.jpg|thumb|Without ''differentials'', you're on the path to ever increasing prescriptions and will get nowhere with vision improvement :(]]
'''Differentials''' ([[EM:JARGON|jargon]]), (''office glasses,'' ''close up'', ''computer use'' or ''diffs'') are reduced strength glasses or lenses for [[close-up|close up activity]]. They have a lower correction than your [[normalized]] lenses, the difference between them being usually between 1 and 2 [[diopters]].<ref>{{cite jake|https://endmyopia.org/faq-items/what-is-the-differential-prescription/|What is the differential prescription?}}</ref><ref name=ChooseReduction>{{cite jake|https://endmyopia.org/choose-reduced-glasses-prescription-differential-close-friendly-glasses/|How To Choose A Reduced Glasses Prescription (Differential / Close-Up Friendly Glasses)}}</ref> These are increasingly available under the name "office glasses" in some parts of Europe (per discord chat comment).

==Low Myopia==
People with myopia of -2 D to -1.5 D and lower do not typically need to wear differentials (because with -2 D your distance till blur should be around 50 cm, and with -1.5 D 67 cm, far enough to see your screen with sufficient clarity). The exception is that if you have more than 1 diopter of cylinder correction you will likely need differentials to help manage directional blur. In this event you likely can reduce the cylinder correction by between .25 and .75 D and pair it with a reduction of up to 1.25 D in spherical strength for either little or no spherical (plano) correction.

=== Last Diopter ===
Below -1 D, unless your close-up distance is around 100cm, you might consider using [[plus lenses]] as a differential. EndMyopia used to specify that they be used for low myopia, but they now consider it is a last resort.

==First Differentials==
The first differentials are typically 1.25 - 1.5 D weaker than your [[measurement]] for full distance vision. If you have -0.25 D of cylinder, you have the option of dropping that. If you have -0.5 to -0.75 D of cylinder, you have the option of dropping that and having the sphere only 1 - 1.25 D weaker.

See [[Lens#How to use Contacts with EM|How to use Contacts with EM]] if you wear contacts.

==Adjusting Differentials==
Ideally your differentials give you a small amount of blur at your daily near work. The nature of your work, the distance to your work, and your [[refractive state]] and [[cylinder]] dependence are all factors in choosing your differentials. The ideal distance for near work is not closer than 50 cm. You may get your first differentials and discover you have a headache and you really shouldn't have dropped cylinder. You may find that your work is pretty close or really far and you need to adjust the strength up or down. You may find that you really need detailed vision to do your work and you'll settle for slowing progression with your differentials and do your blur challenge for improvement in your off hours. This is the first place in the program where you really need to start understanding what you're tinkering with and make personalized diopter specific choices.

==Why are differentials worn?==
The primary stimulus for [[axial elongation]] of the eyeball is [[hyperopic defocus]], which occurs when someone:
* is engaged in close-up activity
* wears more correction than needed when seeing the object that is close up.

Differentials allow the wearer to wear ''just what they need to'', to see up close. This removes the stimulus of hyperopic defocus and stops eyes from getting more myopic. In a sense, it's a [[quick fix]]. {{wink}}

It's fairly easy to stop [[lens-induced myopia]] from progressing by just wearing differentials. The axial length of the eye does not randomly change by itself; it only changes in response to [[stimulus]].

Another reason to wear differentials is to avoid [[convergence]] issues. When viewing in close proximity the position of your eyes needs to compensate by turning in, particularly when you are looking nearer than 50 cm. Doing this for long periods of time on a regular bases is likely to cause issues. Such issues are easily avoided by wearing differential correction to accommodate a larger distance.

== Habits ==
It is useful to apply the [[3 hour rule]]  when engaging in close up (near) work.

Always be mindful to be in a good ergonomic position. Leaning in is a common issue and is something you need to be mindful to avoid.

Good ambient lighting is important because your eyes can not see as far or as well in low lighting. Natural light is best but supplement as needed.

== When are differentials worn ==
Standard EM advice is to wear differentials when looking at static focal planes (e.g. 2D planes like screens, books) at fixed distances for extended periods of time. The main activities EM warns against include screen work, media consumption, and checking phone notifications. It is okay to wear normalized in other contexts, such as when eating a meal, or looking at your conversation partners. It is also permitted to wear differentials in other close-up contexts based on personal preference, but there is no need to overdo normalized/differential glasses changes. (for example, there is no need to swap to differentials whenever someone walks up to you for a conversation)

To determine if a close up activity is hurting your vision with the glasses you are using (differentials or normalized), it helps to have a point of comparison (like a line on a snellen chart), and to compare against that reference point before and after the activity in question.

''' Example scenarios for differentials '''

Read a book with differentials. Use your computer with differentials.

Wear your differential glasses any time you are doing close work. If you have to get up to go to the bathroom, switch back to your normalized glasses. You get used to it pretty fast. "What if I just need to look out my window for like a minute?" CHANGE YOUR GLASSES. If you are asking yourself "should I switch to normalized glasses to look outside the [[blur horizon]] of my differential glasses?" the answer is always YES.

But for convenience, you might choose a threshold time and not change your glasses if it would be worn for less than that threshold. As an example, see the [[20-20-20 rule]] page.

'''What is "close" work?'''

Norms minus diffs = the number of diopters you need to convert to find this answer. For example, if your normalized glasses are -5 and your differential glasses are -3.5, then you need to convert -1.5. You should be able to see 66.67cm with -1.50 myopia! That's about 26.24 inches, or a little more than 2 feet.

== See also ==

* [[Explainer:The_Eyesight_Improvement_Equation#Good_close-up_habits|The Eyesight Improvement Equation: Good close-up habits]]
* [[Normalized#When_do_I_wear_normalized|When do I wear normalized]]
* [[Guide:Reducing differentials]]
* [[Guide:Measuring with differentials]]
* [https://www.youtube.com/watch?v=7HM5oOAexww differentials: a video]
* [https://www.youtube.com/watch?v=EWJxPpSksag Q&A: Reading Books With Differentials - No Blur Horizon?]

==References==
{{reflist}}

[[Category:Articles]]
[[Category:Lens selections]]

Differentials

2023-01-03T03:04:53Z

Snax: /* When are differentials worn */

[[File:Microsoft Cloud Event Dublin, upclose with graphs.jpg|thumb|Without ''differentials'', you're on the path to ever increasing prescriptions and will get nowhere with vision improvement :(]]
'''Differentials''' ([[EM:JARGON|jargon]]), (''office glasses,'' ''close up'', ''computer use'' or ''diffs'') are reduced strength glasses or lenses for [[close-up|close up activity]]. They have a lower correction than your [[normalized]] lenses, the difference between them being usually between 1 and 2 [[diopters]].<ref>{{cite jake|https://endmyopia.org/faq-items/what-is-the-differential-prescription/|What is the differential prescription?}}</ref><ref name=ChooseReduction>{{cite jake|https://endmyopia.org/choose-reduced-glasses-prescription-differential-close-friendly-glasses/|How To Choose A Reduced Glasses Prescription (Differential / Close-Up Friendly Glasses)}}</ref> These are increasingly available under the name "office glasses" in some parts of Europe (per discord chat comment).

==Low Myopia==
People with myopia of -2 D to -1.5 D and lower do not typically need to wear differentials (because with -2 D your distance till blur should be around 50 cm, and with -1.5 D 67 cm, far enough to see your screen with sufficient clarity). The exception is that if you have more than 1 diopter of cylinder correction you will likely need differentials to help manage directional blur. In this event you likely can reduce the cylinder correction by between .25 and .75 D and pair it with a reduction of up to 1.25 D in spherical strength for either little or no spherical (plano) correction.

=== Last Diopter ===
Below -1 D, unless your close-up distance is around 100cm, you might consider using [[plus lenses]] as a differential. EndMyopia used to specify that they be used for low myopia, but they now consider it is a last resort.

==First Differentials==
The first differentials are typically 1.25 - 1.5 D weaker than your [[measurement]] for full distance vision. If you have -0.25 D of cylinder, you have the option of dropping that. If you have -0.5 to -0.75 D of cylinder, you have the option of dropping that and having the sphere only 1 - 1.25 D weaker.

See [[Lens#How to use Contacts with EM|How to use Contacts with EM]] if you wear contacts.

==Adjusting Differentials==
Ideally your differentials give you a small amount of blur at your daily near work. The nature of your work, the distance to your work, and your [[refractive state]] and [[cylinder]] dependence are all factors in choosing your differentials. The ideal distance for near work is not closer than 50 cm. You may get your first differentials and discover you have a headache and you really shouldn't have dropped cylinder. You may find that your work is pretty close or really far and you need to adjust the strength up or down. You may find that you really need detailed vision to do your work and you'll settle for slowing progression with your differentials and do your blur challenge for improvement in your off hours. This is the first place in the program where you really need to start understanding what you're tinkering with and make personalized diopter specific choices.

==Why are differentials worn?==
The primary stimulus for [[axial elongation]] of the eyeball is [[hyperopic defocus]], which occurs when someone:
* is engaged in close-up activity
* wears more correction than needed when seeing the object that is close up.

Differentials allow the wearer to wear ''just what they need to'', to see up close. This removes the stimulus of hyperopic defocus and stops eyes from getting more myopic. In a sense, it's a [[quick fix]]. {{wink}}

It's fairly easy to stop [[lens-induced myopia]] from progressing by just wearing differentials. The axial length of the eye does not randomly change by itself; it only changes in response to [[stimulus]].

Another reason to wear differentials is to avoid [[convergence]] issues. When viewing in close proximity the position of your eyes needs to compensate by turning in, particularly when you are looking nearer than 50 cm. Doing this for long periods of time on a regular bases is likely to cause issues. Such issues are easily avoided by wearing differential correction to accommodate a larger distance.

== Habits ==
It is useful to apply the [[3 hour rule]]  when engaging in close up (near) work.

Always be mindful to be in a good ergonomic position. Leaning in is a common issue and is something you need to be mindful to avoid.

Good ambient lighting is important because your eyes can not see as far or as well in low lighting. Natural light is best but supplement as needed.

== When are differentials worn ==
Standard EM advice is to wear differentials when looking at static focal planes (e.g. 2D planes like screens, books) at fixed distances for extended periods of time. The main activities EM warns against include screen work, media consumption, and checking phone notifications. It is okay to wear normalized in other contexts, such as when eating a meal, or looking at your conversation partners. It is also permitted to wear differentials in other close-up contexts based on personal preference, but there is no need to overdo normalized/differential glasses changes. (for example, there is no need to swap to differentials whenever someone walks up to you for a conversation)

To determine if a close up activity is hurting your vision with the glasses you are using (differentials or normalized), it helps to have a point of comparison (like a line on a snellen chart), and to compare against that reference point before and after the activity in question.

''' Example scenarios for differentials '''

Read a book with differentials. Use your computer with differentials.

Wear your differential glasses any time you are doing close work. If you have to get up to go to the bathroom, switch back to your normalized glasses. You get used to it pretty fast. "What if I just need to look out my window for like a minute?" CHANGE YOUR GLASSES. If you are asking yourself "should I switch to normalized glasses to look outside the [[blur horizon]] of my differential glasses?" the answer is always YES.

But for convenience, you might choose a threshold time and not change your glasses if it would be worn for less than that threshold. As an example, see the [[20-20-20 rule]] page.

'''What is "close" work?'''

Norms minus diffs = the number of diopters you need to convert to find this answer. For example, if your normalized glasses are -5 and your differential glasses are -3.5, then you need to convert -1.5. You should be able to see 66.67cm with -1.50 myopia! That's about 26.24 inches, or a little more than 2 feet.

== See also ==

* [[Explainer:The_Eyesight_Improvement_Equation#Good_close-up_habits|The Eyesight Improvement Equation: Good close-up habits]]
* [[Normalized#When_do_I_wear_normalized|When do I wear normalized]]
* [[Guide:Reducing differentials]]
* [[Guide:Measuring with differentials]]
* [https://www.youtube.com/watch?v=7HM5oOAexww differentials: a video]

==References==
{{reflist}}

[[Category:Articles]]
[[Category:Lens selections]]

Differentials

2023-01-03T03:03:35Z

Snax: /* When are differentials worn */

[[File:Microsoft Cloud Event Dublin, upclose with graphs.jpg|thumb|Without ''differentials'', you're on the path to ever increasing prescriptions and will get nowhere with vision improvement :(]]
'''Differentials''' ([[EM:JARGON|jargon]]), (''office glasses,'' ''close up'', ''computer use'' or ''diffs'') are reduced strength glasses or lenses for [[close-up|close up activity]]. They have a lower correction than your [[normalized]] lenses, the difference between them being usually between 1 and 2 [[diopters]].<ref>{{cite jake|https://endmyopia.org/faq-items/what-is-the-differential-prescription/|What is the differential prescription?}}</ref><ref name=ChooseReduction>{{cite jake|https://endmyopia.org/choose-reduced-glasses-prescription-differential-close-friendly-glasses/|How To Choose A Reduced Glasses Prescription (Differential / Close-Up Friendly Glasses)}}</ref> These are increasingly available under the name "office glasses" in some parts of Europe (per discord chat comment).

==Low Myopia==
People with myopia of -2 D to -1.5 D and lower do not typically need to wear differentials (because with -2 D your distance till blur should be around 50 cm, and with -1.5 D 67 cm, far enough to see your screen with sufficient clarity). The exception is that if you have more than 1 diopter of cylinder correction you will likely need differentials to help manage directional blur. In this event you likely can reduce the cylinder correction by between .25 and .75 D and pair it with a reduction of up to 1.25 D in spherical strength for either little or no spherical (plano) correction.

=== Last Diopter ===
Below -1 D, unless your close-up distance is around 100cm, you might consider using [[plus lenses]] as a differential. EndMyopia used to specify that they be used for low myopia, but they now consider it is a last resort.

==First Differentials==
The first differentials are typically 1.25 - 1.5 D weaker than your [[measurement]] for full distance vision. If you have -0.25 D of cylinder, you have the option of dropping that. If you have -0.5 to -0.75 D of cylinder, you have the option of dropping that and having the sphere only 1 - 1.25 D weaker.

See [[Lens#How to use Contacts with EM|How to use Contacts with EM]] if you wear contacts.

==Adjusting Differentials==
Ideally your differentials give you a small amount of blur at your daily near work. The nature of your work, the distance to your work, and your [[refractive state]] and [[cylinder]] dependence are all factors in choosing your differentials. The ideal distance for near work is not closer than 50 cm. You may get your first differentials and discover you have a headache and you really shouldn't have dropped cylinder. You may find that your work is pretty close or really far and you need to adjust the strength up or down. You may find that you really need detailed vision to do your work and you'll settle for slowing progression with your differentials and do your blur challenge for improvement in your off hours. This is the first place in the program where you really need to start understanding what you're tinkering with and make personalized diopter specific choices.

==Why are differentials worn?==
The primary stimulus for [[axial elongation]] of the eyeball is [[hyperopic defocus]], which occurs when someone:
* is engaged in close-up activity
* wears more correction than needed when seeing the object that is close up.

Differentials allow the wearer to wear ''just what they need to'', to see up close. This removes the stimulus of hyperopic defocus and stops eyes from getting more myopic. In a sense, it's a [[quick fix]]. {{wink}}

It's fairly easy to stop [[lens-induced myopia]] from progressing by just wearing differentials. The axial length of the eye does not randomly change by itself; it only changes in response to [[stimulus]].

Another reason to wear differentials is to avoid [[convergence]] issues. When viewing in close proximity the position of your eyes needs to compensate by turning in, particularly when you are looking nearer than 50 cm. Doing this for long periods of time on a regular bases is likely to cause issues. Such issues are easily avoided by wearing differential correction to accommodate a larger distance.

== Habits ==
It is useful to apply the [[3 hour rule]]  when engaging in close up (near) work.

Always be mindful to be in a good ergonomic position. Leaning in is a common issue and is something you need to be mindful to avoid.

Good ambient lighting is important because your eyes can not see as far or as well in low lighting. Natural light is best but supplement as needed.

== When are differentials worn ==
Standard EM advice is to wear differentials when looking at static focal planes (e.g. 2D planes like screens, books) at fixed distances for extended periods of time. The main activities EM warns about include screen work, media consumption, and checking phone notifications. It is okay to wear normalized in other contexts, such as when eating a meal, or looking at your conversation partners. It is also permitted to wear differentials in other close-up contexts based on personal preference, but there is no need to overdo normalized/differential glasses changes. (for example, there is no need to swap to differentials whenever someone walks up to you for a conversation)

To determine if a close up activity is hurting your vision with the glasses you are using (differentials or normalized), it helps to have a point of comparison (like a line on a snellen chart), and to compare against that reference point before and after the activity in question.

''' Example scenarios for differentials '''

Read a book with differentials. Use your computer with differentials.

Wear your differential glasses any time you are doing close work. If you have to get up to go to the bathroom, switch back to your normalized glasses. You get used to it pretty fast. "What if I just need to look out my window for like a minute?" CHANGE YOUR GLASSES. If you are asking yourself "should I switch to normalized glasses to look outside the [[blur horizon]] of my differential glasses?" the answer is always YES.

But for convenience, you might choose a threshold time and not change your glasses if it would be worn for less than that threshold. As an example, see the [[20-20-20 rule]] page.

'''What is "close" work?'''

Norms minus diffs = the number of diopters you need to convert to find this answer. For example, if your normalized glasses are -5 and your differential glasses are -3.5, then you need to convert -1.5. You should be able to see 66.67cm with -1.50 myopia! That's about 26.24 inches, or a little more than 2 feet.

== See also ==

* [[Explainer:The_Eyesight_Improvement_Equation#Good_close-up_habits|The Eyesight Improvement Equation: Good close-up habits]]
* [[Normalized#When_do_I_wear_normalized|When do I wear normalized]]
* [[Guide:Reducing differentials]]
* [[Guide:Measuring with differentials]]
* [https://www.youtube.com/watch?v=7HM5oOAexww differentials: a video]

==References==
{{reflist}}

[[Category:Articles]]
[[Category:Lens selections]]

Peak Prescription

2023-01-02T05:54:19Z

Snax:

Also known as "Peak Diopters".

Use of Peak Prescription is considered an advanced troubleshooting technique, so when it doubt, stick to only having two glasses, normalized and differentials.

A Peak Prescription is [https://endmyopia.org/alex-unlock-one-diopter-margin-vision/ your next] [[Normalized]]. Alternatively, you can use old differentials (with their stronger diopters than current differentials) as a peak prescription.

It could be [https://endmyopia.org/what-you-missed-the-peak-prescription/ used when the Normalized has too much correction], but be careful not to use too many focal planes.

It is useful for [https://endmyopia.org/how-to-getting-the-most-out-of-your-peak-prescription/ measuring close-up strain].

It is also useful for [https://endmyopia.org/alex-unlock-one-diopter-margin-vision/ this exercise].

The EM blog has an example where [https://endmyopia.org/part-2-improvements/ the peak prescription (and therefore next normalized) is -8, which is 1.5 D under the current normalized of -9].

Only start using peak diopters when you are not getting stimulus from your current normalized, or if you are troubleshooting a plateau. When getting used to a reduction (whether current normalized, or next normalized), it is better to have only one pair of glasses you are getting acclimated to at a time,.

'''EM Protocol for Peak Prescription'''
* [Option A] Start days without glasses (zero diopter reset)
* [Option B] Start days with differentials (particularly if personal myopia level is too high to be comfortable for the start of the day)
* Switch to the peak diopters in peak conditions (like a brightly lit morning walk) for 30-120 minutes of an active focus promoting activity. Proceed to the next step of using normalized glasses earlier if you feel fatigue.
* Switch to your current normalized for the rest of the day.

Over time, move toward using peak prescription as the next normalized, as that pair of glasses becomes more comfortable to use.

Avoid introducing too many focal planes too early. Switching frequently between two unfamiliar reduction glasses has anecdotally stalled progress, so make sure current normalized adaptation is locked in before introducing peak diopters.

[[Category:Articles]]
[[Category:Lens selections]]

Peak Prescription

2023-01-02T05:53:02Z

Snax:

Also known as "Peak Diopters".

Use of Peak Prescription is considered an advanced troubleshooting technique, so when it doubt, stick to only having two glasses, normalized and differentials.

A Peak Prescription is [https://endmyopia.org/alex-unlock-one-diopter-margin-vision/ your next] [[Normalized]]. Alternatively, you can use old differentials as a peak prescription.

It could be [https://endmyopia.org/what-you-missed-the-peak-prescription/ used when the Normalized has too much correction], but be careful not to use too many focal planes.

It is useful for [https://endmyopia.org/how-to-getting-the-most-out-of-your-peak-prescription/ measuring close-up strain].

It is also useful for [https://endmyopia.org/alex-unlock-one-diopter-margin-vision/ this exercise].

The EM blog has an example where [https://endmyopia.org/part-2-improvements/ the peak prescription (and therefore next normalized) is -8, which is 1.5 D under the current normalized of -9].

Only start using peak diopters when you are not getting stimulus from your current normalized, or if you are troubleshooting a plateau. When getting used to a reduction (whether current normalized, or next normalized), it is better to have only one pair of glasses you are getting acclimated to at a time,.

'''EM Protocol for Peak Prescription'''
* [Option A] Start days without glasses (zero diopter reset)
* [Option B] Start days with differentials (particularly if personal myopia level is too high to be comfortable for the start of the day)
* Switch to the peak diopters in peak conditions (like a brightly lit morning walk) for 30-120 minutes of an active focus promoting activity. Proceed to the next step of using normalized glasses earlier if you feel fatigue.
* Switch to your current normalized for the rest of the day.

Over time, move toward using peak prescription as the next normalized, as that pair of glasses becomes more comfortable to use.

Avoid introducing too many focal planes too early. Switching frequently between two unfamiliar reduction glasses has anecdotally stalled progress, so make sure current normalized adaptation is locked in before introducing peak diopters.

[[Category:Articles]]
[[Category:Lens selections]]

Peak Prescription

2023-01-02T05:45:30Z

Snax:

Also known as "Peak Diopters".

Use of Peak Prescription is considered an advanced troubleshooting technique, so when it doubt, stick to only having two glasses, normalized and differentials.

A Peak Prescription is [https://endmyopia.org/alex-unlock-one-diopter-margin-vision/ your next] [[Normalized]].

It could be [https://endmyopia.org/what-you-missed-the-peak-prescription/ used when the Normalized has too much correction], but be careful not to use too many focal planes.

It is useful for [https://endmyopia.org/how-to-getting-the-most-out-of-your-peak-prescription/ measuring close-up strain].

It is also useful for [https://endmyopia.org/alex-unlock-one-diopter-margin-vision/ this exercise].

The EM blog has an example where [https://endmyopia.org/part-2-improvements/ the peak prescription (and therefore next normalized) is -8, which is 1.5 D under the current normalized of -9].

Only start using peak diopters when you are not getting stimulus from your current normalized, or if you are troubleshooting a plateau. When getting used to a reduction (whether current normalized, or next normalized), it is better to have only one pair of glasses you are getting acclimated to at a time,.

'''EM Protocol for Peak Prescription'''
* [Option A] Start days without glasses (zero diopter reset)
* [Option B] Start days with differentials (particularly if personal myopia level is too high to be comfortable for the start of the day)
* Switch to the peak diopters in peak conditions (like a brightly lit morning walk) for 30-120 minutes of an active focus promoting activity. Proceed to the next step of using normalized glasses earlier if you feel fatigue.
* Switch to your current normalized for the rest of the day.

Over time, move toward using peak prescription as the next normalized, as that pair of glasses becomes more comfortable to use.

Avoid introducing too many focal planes too early. Switching frequently between two unfamiliar reduction glasses has anecdotally stalled progress, so make sure current normalized adaptation is locked in before introducing peak diopters.

[[Category:Articles]]
[[Category:Lens selections]]

Differentials

2023-01-02T05:16:11Z

Snax: /* When are differentials worn */

[[File:Microsoft Cloud Event Dublin, upclose with graphs.jpg|thumb|Without ''differentials'', you're on the path to ever increasing prescriptions and will get nowhere with vision improvement :(]]
'''Differentials''' ([[EM:JARGON|jargon]]), (''office glasses,'' ''close up'', ''computer use'' or ''diffs'') are reduced strength glasses or lenses for [[close-up|close up activity]]. They have a lower correction than your [[normalized]] lenses, the difference between them being usually between 1 and 2 [[diopters]].<ref>{{cite jake|https://endmyopia.org/faq-items/what-is-the-differential-prescription/|What is the differential prescription?}}</ref><ref name=ChooseReduction>{{cite jake|https://endmyopia.org/choose-reduced-glasses-prescription-differential-close-friendly-glasses/|How To Choose A Reduced Glasses Prescription (Differential / Close-Up Friendly Glasses)}}</ref> These are increasingly available under the name "office glasses" in some parts of Europe (per discord chat comment).

==Low Myopia==
People with myopia of -2 D to -1.5 D and lower do not typically need to wear differentials (because with -2 D your distance till blur should be around 50 cm, and with -1.5 D 67 cm, far enough to see your screen with sufficient clarity). The exception is that if you have more than 1 diopter of cylinder correction you will likely need differentials to help manage directional blur. In this event you likely can reduce the cylinder correction by between .25 and .75 D and pair it with a reduction of up to 1.25 D in spherical strength for either little or no spherical (plano) correction.

=== Last Diopter ===
Below -1 D, unless your close-up distance is around 100cm, you might consider using [[plus lenses]] as a differential. EndMyopia used to specify that they be used for low myopia, but they now consider it is a last resort.

==First Differentials==
The first differentials are typically 1.25 - 1.5 D weaker than your [[measurement]] for full distance vision. If you have -0.25 D of cylinder, you have the option of dropping that. If you have -0.5 to -0.75 D of cylinder, you have the option of dropping that and having the sphere only 1 - 1.25 D weaker.

See [[Lens#How to use Contacts with EM|How to use Contacts with EM]] if you wear contacts.

==Adjusting Differentials==
Ideally your differentials give you a small amount of blur at your daily near work. The nature of your work, the distance to your work, and your [[refractive state]] and [[cylinder]] dependence are all factors in choosing your differentials. The ideal distance for near work is not closer than 50 cm. You may get your first differentials and discover you have a headache and you really shouldn't have dropped cylinder. You may find that your work is pretty close or really far and you need to adjust the strength up or down. You may find that you really need detailed vision to do your work and you'll settle for slowing progression with your differentials and do your blur challenge for improvement in your off hours. This is the first place in the program where you really need to start understanding what you're tinkering with and make personalized diopter specific choices.

==Why are differentials worn?==
The primary stimulus for [[axial elongation]] of the eyeball is [[hyperopic defocus]], which occurs when someone:
* is engaged in close-up activity
* wears more correction than needed when seeing the object that is close up.

Differentials allow the wearer to wear ''just what they need to'', to see up close. This removes the stimulus of hyperopic defocus and stops eyes from getting more myopic. In a sense, it's a [[quick fix]]. {{wink}}

It's fairly easy to stop [[lens-induced myopia]] from progressing by just wearing differentials. The axial length of the eye does not randomly change by itself; it only changes in response to [[stimulus]].

Another reason to wear differentials is to avoid [[convergence]] issues. When viewing in close proximity the position of your eyes needs to compensate by turning in, particularly when you are looking nearer than 50 cm. Doing this for long periods of time on a regular bases is likely to cause issues. Such issues are easily avoided by wearing differential correction to accommodate a larger distance.

== Habits ==
It is useful to apply the [[3 hour rule]]  when engaging in close up (near) work.

Always be mindful to be in a good ergonomic position. Leaning in is a common issue and is something you need to be mindful to avoid.

Good ambient lighting is important because your eyes can not see as far or as well in low lighting. Natural light is best but supplement as needed.

== When are differentials worn ==
Standard EM advice is to wear differentials when looking at static focal planes (e.g. 2D planes like screens, books) at fixed distances for extended periods of time. It is okay to wear normalized in other contexts, such as when eating a meal, or looking at your conversation partners. It is also permitted to wear differentials in other close-up contexts based on personal preference, but there is no need to overdo normalized/differential glasses changes. (for example, there is no need to swap to differentials whenever someone walks up to you for a conversation)

To determine if a close up activity is hurting your vision with the glasses you are using (differentials or normalized), it helps to have a point of comparison (like a line on a snellen chart), and to compare against that reference point before and after the activity in question.

''' Example scenarios for differentials '''

Read a book with differentials. Use your computer with differentials.

Wear your differential glasses any time you are doing close work. If you have to get up to go to the bathroom, switch back to your normalized glasses. You get used to it pretty fast. "What if I just need to look out my window for like a minute?" CHANGE YOUR GLASSES. If you are asking yourself "should I switch to normalized glasses to look outside the [[blur horizon]] of my differential glasses?" the answer is always YES.

But for convenience, you might choose a threshold time and not change your glasses if it would be worn for less than that threshold. As an example, see the [[20-20-20 rule]] page.

'''What is "close" work?'''

Norms minus diffs = the number of diopters you need to convert to find this answer. For example, if your normalized glasses are -5 and your differential glasses are -3.5, then you need to convert -1.5. You should be able to see 66.67cm with -1.50 myopia! That's about 26.24 inches, or a little more than 2 feet.

== See also ==

* [[Explainer:The_Eyesight_Improvement_Equation#Good_close-up_habits|The Eyesight Improvement Equation: Good close-up habits]]
* [[Normalized#When_do_I_wear_normalized|When do I wear normalized]]
* [[Guide:Reducing differentials]]
* [[Guide:Measuring with differentials]]
* [https://www.youtube.com/watch?v=7HM5oOAexww differentials: a video]

==References==
{{reflist}}

[[Category:Articles]]
[[Category:Lens selections]]

Differentials

2023-01-02T05:13:54Z

Snax: /* When are differentials worn */

[[File:Microsoft Cloud Event Dublin, upclose with graphs.jpg|thumb|Without ''differentials'', you're on the path to ever increasing prescriptions and will get nowhere with vision improvement :(]]
'''Differentials''' ([[EM:JARGON|jargon]]), (''office glasses,'' ''close up'', ''computer use'' or ''diffs'') are reduced strength glasses or lenses for [[close-up|close up activity]]. They have a lower correction than your [[normalized]] lenses, the difference between them being usually between 1 and 2 [[diopters]].<ref>{{cite jake|https://endmyopia.org/faq-items/what-is-the-differential-prescription/|What is the differential prescription?}}</ref><ref name=ChooseReduction>{{cite jake|https://endmyopia.org/choose-reduced-glasses-prescription-differential-close-friendly-glasses/|How To Choose A Reduced Glasses Prescription (Differential / Close-Up Friendly Glasses)}}</ref> These are increasingly available under the name "office glasses" in some parts of Europe (per discord chat comment).

==Low Myopia==
People with myopia of -2 D to -1.5 D and lower do not typically need to wear differentials (because with -2 D your distance till blur should be around 50 cm, and with -1.5 D 67 cm, far enough to see your screen with sufficient clarity). The exception is that if you have more than 1 diopter of cylinder correction you will likely need differentials to help manage directional blur. In this event you likely can reduce the cylinder correction by between .25 and .75 D and pair it with a reduction of up to 1.25 D in spherical strength for either little or no spherical (plano) correction.

=== Last Diopter ===
Below -1 D, unless your close-up distance is around 100cm, you might consider using [[plus lenses]] as a differential. EndMyopia used to specify that they be used for low myopia, but they now consider it is a last resort.

==First Differentials==
The first differentials are typically 1.25 - 1.5 D weaker than your [[measurement]] for full distance vision. If you have -0.25 D of cylinder, you have the option of dropping that. If you have -0.5 to -0.75 D of cylinder, you have the option of dropping that and having the sphere only 1 - 1.25 D weaker.

See [[Lens#How to use Contacts with EM|How to use Contacts with EM]] if you wear contacts.

==Adjusting Differentials==
Ideally your differentials give you a small amount of blur at your daily near work. The nature of your work, the distance to your work, and your [[refractive state]] and [[cylinder]] dependence are all factors in choosing your differentials. The ideal distance for near work is not closer than 50 cm. You may get your first differentials and discover you have a headache and you really shouldn't have dropped cylinder. You may find that your work is pretty close or really far and you need to adjust the strength up or down. You may find that you really need detailed vision to do your work and you'll settle for slowing progression with your differentials and do your blur challenge for improvement in your off hours. This is the first place in the program where you really need to start understanding what you're tinkering with and make personalized diopter specific choices.

==Why are differentials worn?==
The primary stimulus for [[axial elongation]] of the eyeball is [[hyperopic defocus]], which occurs when someone:
* is engaged in close-up activity
* wears more correction than needed when seeing the object that is close up.

Differentials allow the wearer to wear ''just what they need to'', to see up close. This removes the stimulus of hyperopic defocus and stops eyes from getting more myopic. In a sense, it's a [[quick fix]]. {{wink}}

It's fairly easy to stop [[lens-induced myopia]] from progressing by just wearing differentials. The axial length of the eye does not randomly change by itself; it only changes in response to [[stimulus]].

Another reason to wear differentials is to avoid [[convergence]] issues. When viewing in close proximity the position of your eyes needs to compensate by turning in, particularly when you are looking nearer than 50 cm. Doing this for long periods of time on a regular bases is likely to cause issues. Such issues are easily avoided by wearing differential correction to accommodate a larger distance.

== Habits ==
It is useful to apply the [[3 hour rule]]  when engaging in close up (near) work.

Always be mindful to be in a good ergonomic position. Leaning in is a common issue and is something you need to be mindful to avoid.

Good ambient lighting is important because your eyes can not see as far or as well in low lighting. Natural light is best but supplement as needed.

== When are differentials worn ==
Standard EM advice is to wear differentials when looking at static focal planes (e.g. 2D planes like screens, books) at fixed distances for extended periods of time. It is okay to wear normalized in other contexts, such as when eating a meal, or looking at your conversation partners. It is also permitted to wear differentials in other close-up contexts based on personal preference, but there is no need to overdo normalized/differential glasses changes. (for example, there is no need to swap to differentials whenever someone walks up to you for a conversation)

To determine if a close up activity is hurting your vision with the glasses you are using (differentials or normalized), it helps to have a point of comparison (like a line on a snellen chart), and to compare against that reference point before and after the activity in question.

Read a book with differentials. Use your computer with differentials.

Wear your differential glasses any time you are doing close work. If you have to get up to go to the bathroom, switch back to your normalized glasses. You get used to it pretty fast. "What if I just need to look out my window for like a minute?" CHANGE YOUR GLASSES. If you are asking yourself "should I switch to normalized glasses to look outside the [[blur horizon]] of my differential glasses?" the answer is always YES.

But for convenience, you might choose a threshold time and not change your glasses if it would be worn for less than that threshold. As an example, see the [[20-20-20 rule]] page.

'''What is "close" work?'''

Norms minus diffs = the number of diopters you need to convert to find this answer. For example, if your normalized glasses are -5 and your differential glasses are -3.5, then you need to convert -1.5. You should be able to see 66.67cm with -1.50 myopia! That's about 26.24 inches, or a little more than 2 feet.

== See also ==

* [[Explainer:The_Eyesight_Improvement_Equation#Good_close-up_habits|The Eyesight Improvement Equation: Good close-up habits]]
* [[Normalized#When_do_I_wear_normalized|When do I wear normalized]]
* [[Guide:Reducing differentials]]
* [[Guide:Measuring with differentials]]
* [https://www.youtube.com/watch?v=7HM5oOAexww differentials: a video]

==References==
{{reflist}}

[[Category:Articles]]
[[Category:Lens selections]]

Snellen chart

2022-10-16T21:04:12Z

Snax: /* Tools */

{{Infobox diagnostic
| name = Snellen chart
| image = Snellen chart.svg
| alt =
| caption =
| pronounce =
| purpose = Snellen chart is used to estimate visual acuity
| test of =
| based on =
| synonyms =
| reference_range =
| calculator =
| DiseasesDB = 
| ICD10 = 
| ICD9 =
| ICDO =
| MedlinePlus = 
| eMedicine = 
| MeshID =
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| LOINC = 
}}
A '''Snellen chart''' is a standard method of measuring [[visual acuity]]. A chart is rated for the distance it should be viewed at, and the lowest line that can be read has a visual acuity result number next to it. The standard distance for Snellen charts is 20 feet or 6 meters. Smaller versions are available for use in smaller indoor spaces. Generally, most myopes can be corrected to the [[20/20]] line unless they have visual acuity problems other than myopia. There is no direct correlation between visual acuity and [[myopia]]. The Snellen chart is the most commonly used way of testing if someone has sufficient corrected visual acuity to drive legally. Your [[optometrist]] will use the Snellen chart as a reference, to see what refraction will allow you to read the lowest on the chart.
{{clear}}
==Definition of the numbers==

The acuity is expressed as the ratio of the distance (usually 20ft or 6m but can be less) to the letter size, expressed as the distance at which the letter subtends an angle of 5 arc-minutes. (Or equivalently, as multiples of the height at which the letter subtends 5 arc-minutes at a distance of 1 unit of distance). 5 arc-minutes just means 5/60 of a degree. So
* 20/20 means 5 arc-minutes at 20 feet
* 20/16 means 4 arc-minutes at 20 feet
* 6/12 means 10 arc-minutes at 6m

The critical gaps that need to be resolved are 1 arc-minute, so that's really what defines the required acuity.

==How to use a Snellen Chart to measure visual acuity==
# Read the documentation that came with your chart to determine what distance it is designed to be viewed at. This is usually 10 feet, 20 feet, 3 m or 6m. It may say right on the chart, on the back, or in the description of the product where you got it.
# Post the chart at eye level
# Make a mark on the floor at the distance the chart is rated for.
# Stand so that your face is above that line.
# Read the lowest line you can see clearly.
# Attempt to read the next line down.
# Have an assistant tell you if you got the letters right or move forward to check. If you got more than half of the letters right on that line, then the ratio marked for that line is your visual acuity.

==How to use a Snellen Chart with refraction==
{{main|Trial lens kit}}

==Tools==
* [http://www.i-see.org/block_letter_eye_chart.pdf Block Letter Eye Chart with calibration measurement instructions 20feet/6meters)]
* [http://www.i-see.org/etdrs/etdrs-1.pdf ETDRS Snellen version 1 20feet/6meters]
* [http://www.i-see.org/etdrs/etdrs-2.pdf ETDRS Snellen version 2 20feet/6meters]

* [http://www.i-see.org/etdrs/etdrs-r.pdf ETDRS Snellen version 3 20feet/6meters]

* [https://www.provisu.ch/images/PDF/Snellenchart_en.pdf Printable Snellen Chart 2.8m(9 feet)]
* [https://www.teachengineering.org/content/cub_/activities/cub_human/cub_human_lesson06_activity1_eyechart.pdf Printable Snellen Eye Chart 6m(20 feet)]
* [https://github.com/mminer237/denim-weasel Snellen chart generator]
* [https://eyes.arizona.edu/sites/default/files/eyechart.pdf Banner Eye Care Visual Acuity Test (BECVAT) V 2.0]
* Some people with astigmatism may use the [https://en.wikipedia.org/wiki/Stenopaeic_slit stenopaeic slit]<ref>https://community.endmyopia.org/t/francois-journey-to-20-20/10428/3</ref> as a measuring tool
* Alternatively, you can use an [http://www.i-see.org/astigmirror.pdf astigmatism mirror/fan] along with [https://endmyopia.org/diy-tools-how-to-measure-your-astigmatism-diopters/ this guide for estimating astigmatism].

==See Also==

* [[Astigmatism_measurement]]

==References==
{{reflist}}

[[Category:Articles]]

Cylinder

2022-10-10T19:00:48Z

Snax:

'''Cylinder''' lenses correct for the most common kind of [[astigmatism]]. It's represented as CYL on [[prescriptions]]. The lens is shaped like a cylinder rather than a sphere, bending light in one direction, but not in the other. The direction is specified by the [[Axis]].

==Positive vs. Negative Cylinder==
Eyecare professionals have individual preferences for writing out positive vs negative values for cyl. For discussion with other EM participants, it is usually recommended to convert positive cylinder values into their negative equivalent, as the negative cylinder values are potentially more intuitive from a reduction point of view.

* For example, there are participants who get surprised [https://www.youtube.com/watch?v=AJQEdXwKiNA&t=1363s when they remove plus cylinder, and then find that the glasses they order are too strong].
* [https://www.aclens.com/positive-cyl-converter There are tools that will convert between equivalent prescriptions of plus or negative cylinder]
* [https://www.youtube.com/watch?v=0AyE1BmKUh8 Gemily's video explaining plus vs negative cylinder]

==References==
{{reflist}}

[[Category:Articles]]

Myopia is Mental

2022-10-10T05:14:30Z

Snax: /* Criticism */

[https://www.myopiaismental.com/ Myopia is Mental]

[https://www.youtube.com/user/markhyo YouTube Channel]

'''Myopia is Mental''' is a vision improvement method created by Mark Warren.

Emphasizes noticing the relative movement of objects in [[peripheral vision]] as a way to relax the eye for clearer vision. Suggests that [[tunnel vision]] can cause people to not notice peripheral vision, keeping the eyes in a tensed state.

The method has existed since the start of 2020.

==Criticism==

Myopia is Mental has been criticized as lacking details on certain topics, such as how to handle complex glasses prescription ([https://www.myopiaismental.com/faqs There is an emphasis on significantly reduced or no correction.]). Emphasizes [[clear flashes]] as a signal for improvement, which may be hard to reproduce consistently across various individuals. It also ignores the scientific consensus that [[myopia]] is caused by a longer [[axial length]] of the eyeball, [https://www.youtube.com/watch?v=S0rXN4C-sKY by suggesting that the eye is squeezed by chronic tension]:

: I believe both. Tension is the enemy in both cases. Too much tension in the ciliary body makes the muscle stiff so now the lens can't move/focus. The lens can become hardened over time from lack of movement. Think about an engine that sits for a long period of time. It can eventually deadlock. As for eye elongation. I don't think the eyes grow long or rather grow at all. I believe the tension caused my the extraocular muscles squish the eyeball to make it long. Think about a round balloon and you use your hand to smash it down. It becomes long. Learn to relieve the tension in both the ciliary and extraocular muscles and you fix both!

There are other writings that indicate that MiM advocates that [https://www.myopiaismental.com/why-i-think-its-mental-and-why-i-started-mim/ myopia is more mental than physical]. This clashes with EM's view that myopia is related to the physical shape of the eye, and that any changes need to be measured and gradual to prevent issues with too much changes in the eye being too difficult for the brain to adapt to (which may manifest as double vision or eye discomfort).

MiM also encourages chasing a feeling of stinging or watering in the eyes while practicing active focus. EM strongly cautions against this attitude, instead recommending that any pain should be used as a hint to moderate any behavior. Rule of thumb for EM: If it hurts, you really should consider stopping what you are doing that is causing the pain.

Marks [https://community.endmyopia.org/t/an-easy-way-to-achieve-active-focus/6807 claims] to have improved from "Left -5.00 with a -1.00 / 80 axis for astigmatism and Right -4.0" to "-1.50 in both eyes" between the periods of November 2018 thru August 2019. This is considered very fast improvement by EM standards, and not considered a realistic improvement rate by both EM and mainstream optometry standards. (EM suggests that a good improvement rate is 0.75-1.00 diopters a year, while mainstream optometry says that myopia reversal is impossible.)

Do feel free to give it a go. Make your own mind up - be skeptical and avoid blind belief: [[Blind belief]].

There's a minority contingent of EM participants who find the material interesting from the angle of learning about what to notice in peripheral vision.

==Habits, practices, and concepts suggested by Mark Warren==

* [https://www.youtube.com/watch?v=ccgw6WODV90 Tracking multiple objects in 3D space], to aid with "automatic focus" (Myopia is Mental's rephrasing of [[Active Focus]]). Specifically, noticing the relative movement of all objects in your awareness as you change your focus between objects at different distances while slowly moving your head position.

* "Rocking" exercise by moving one's body so that the head is moving side to side while the eyes are looking at various objects of interest. To be practiced with multi-object tracking above.

* [https://www.youtube.com/watch?v=RfO0x9uIkTQ Stationary movement] exercise by rotating one's head while tracking multiple objects at different ranges, and noticing that relative movement between objects changes with distance.

* Combining the practices of multi-object tracking and "stationary movement" by talking walks to see how objects move relative to each other as you move in different directions (either by turning in place, or by walking away/toward/past objects).

* Maintaining awareness of peripheral vision even when looking at objects in central vision. A specific technique Mark calls "peripheral triangulation" involves looking at a target object with your central vision, while noticing the positions and distances of objects in the peripheral awareness relative to the target object in view. One suggestion [https://www.youtube.com/watch?v=S0rXN4C-sKY mentioned in a video comments thread] is to turn on a muted TV as a peripheral vision background while looking at a central vision target:

: "A lot of people say the peripheral isn't important but I'm going to tell you why many have trouble seeing the full field of view while looking at something with their central vision. . If you spend a lot of times indoors in rooms, you're surrounded by stationary objects that don't move. This isn't natural! The only way for them to move is for "you" to move! If you think about being outside in nature, nothing is ever perfectly still! The wind blows ever so slightly and it will cause trees, plants and flowers to sway. Also you don't sit in square, confined boxes in nature (which is why it's easier to improve vision outdoors vs indoors). To improve your ability to see movement indoors try reading with a TV running in the background to your left or right. Turn the sound off so you're not distracted by it, but as you read notice the movement on the TV as you read. I'm actually doing this while I type this reply!"

* [https://community.endmyopia.org/t/an-easy-way-to-achieve-active-focus/6807 EM Forum thread where Mark Warren explains his theories on Active Focus]

== One unofficial analogy to think about the above techniques ==

... is that they are all combined to perform a human [https://en.wikipedia.org/wiki/Simultaneous_localization_and_mapping simultaneous localization and mapping], which is a concept normally utilized in the domain of robotics. For a robot to locate itself in an environment using a video camera, the robot needs to track the positions of various features it can recognize in its vision. Robots that are tracking their movement can use the relative movement between objects in a video image to estimate distance. "Stationary movement" is analogous to a robot rotating its camera and tracking the relative movement of objects in the camera image (to oversimplify, you can calculate the distances of the tracked objects by processing the geometry of the object movement combined with the known angle of rotation).

[https://www.youtube.com/watch?v=7Hlb8YX2-W8&t=35440s To illustrate the above concepts, here's a video timestamp of a programmer creating a 3D model of a world just from a 2D video.]

[[Category:Unicorn Farming]]

Myopia is Mental

2022-10-10T05:13:24Z

Snax: /* Criticism */

[https://www.myopiaismental.com/ Myopia is Mental]

[https://www.youtube.com/user/markhyo YouTube Channel]

'''Myopia is Mental''' is a vision improvement method created by Mark Warren.

Emphasizes noticing the relative movement of objects in [[peripheral vision]] as a way to relax the eye for clearer vision. Suggests that [[tunnel vision]] can cause people to not notice peripheral vision, keeping the eyes in a tensed state.

The method has existed since the start of 2020.

==Criticism==

Myopia is Mental has been criticized as lacking details on certain topics, such as how to handle complex glasses prescription ([https://www.myopiaismental.com/faqs There is an emphasis on significantly reduced or no correction.]). Emphasizes [[clear flashes]] as a signal for improvement, which may be hard to reproduce consistently across various individuals. It also ignores the scientific consensus that [[myopia]] is caused by a longer [[axial length]] of the eyeball, [https://www.youtube.com/watch?v=S0rXN4C-sKY by suggesting that the eye is squeezed by chronic tension]:

: I believe both. Tension is the enemy in both cases. Too much tension in the ciliary body makes the muscle stiff so now the lens can't move/focus. The lens can become hardened over time from lack of movement. Think about an engine that sits for a long period of time. It can eventually deadlock. As for eye elongation. I don't think the eyes grow long or rather grow at all. I believe the tension caused my the extraocular muscles squish the eyeball to make it long. Think about a round balloon and you use your hand to smash it down. It becomes long. Learn to relieve the tension in both the ciliary and extraocular muscles and you fix both!

There are other writings that indicate that MiM advocates that [https://www.myopiaismental.com/why-i-think-its-mental-and-why-i-started-mim/ myopia is more mental than physical]. This clashes with EM's view that myopia is related to the physical shape of the eye, and that any changes need to be measured and gradual to prevent issues with too much changes in the eye being too difficult for the brain to adapt to (which may manifest as double vision or eye discomfort).

MiM also encourages chasing a feeling of stinging or watering in the eyes while practicing active focus. EM strongly cautions against this attitude, instead recommending that any pain should be used as a hint to moderate any behavior. Rule of thumb for EM: If it hurts, you really should consider stopping what you are doing that is causing the pain.

Marks [https://community.endmyopia.org/t/an-easy-way-to-achieve-active-focus/6807 claims] to have improved from "Left -5.00 with a -1.00 / 80 axis for astigmatism and Right -4.0" to "-1.50 in both eyes" between the periods of November 2018 thru August 2019. This is considered very fast improvement by EM standards, and not considered a realistic improvement rate by both EM and mainstream optometry standards. (EM suggests that a good improvement rate is 0.75-1.00 diopters a year, while mainstream optometry says that myopia reversal is impossible.)

Do feel free to give it a go. Make your own mind up - be skeptical and avoid [[Blind belief]].

There's a minority contingent of EM participants who find the material interesting from the angle of learning about what to notice in peripheral vision.

==Habits, practices, and concepts suggested by Mark Warren==

* [https://www.youtube.com/watch?v=ccgw6WODV90 Tracking multiple objects in 3D space], to aid with "automatic focus" (Myopia is Mental's rephrasing of [[Active Focus]]). Specifically, noticing the relative movement of all objects in your awareness as you change your focus between objects at different distances while slowly moving your head position.

* "Rocking" exercise by moving one's body so that the head is moving side to side while the eyes are looking at various objects of interest. To be practiced with multi-object tracking above.

* [https://www.youtube.com/watch?v=RfO0x9uIkTQ Stationary movement] exercise by rotating one's head while tracking multiple objects at different ranges, and noticing that relative movement between objects changes with distance.

* Combining the practices of multi-object tracking and "stationary movement" by talking walks to see how objects move relative to each other as you move in different directions (either by turning in place, or by walking away/toward/past objects).

* Maintaining awareness of peripheral vision even when looking at objects in central vision. A specific technique Mark calls "peripheral triangulation" involves looking at a target object with your central vision, while noticing the positions and distances of objects in the peripheral awareness relative to the target object in view. One suggestion [https://www.youtube.com/watch?v=S0rXN4C-sKY mentioned in a video comments thread] is to turn on a muted TV as a peripheral vision background while looking at a central vision target:

: "A lot of people say the peripheral isn't important but I'm going to tell you why many have trouble seeing the full field of view while looking at something with their central vision. . If you spend a lot of times indoors in rooms, you're surrounded by stationary objects that don't move. This isn't natural! The only way for them to move is for "you" to move! If you think about being outside in nature, nothing is ever perfectly still! The wind blows ever so slightly and it will cause trees, plants and flowers to sway. Also you don't sit in square, confined boxes in nature (which is why it's easier to improve vision outdoors vs indoors). To improve your ability to see movement indoors try reading with a TV running in the background to your left or right. Turn the sound off so you're not distracted by it, but as you read notice the movement on the TV as you read. I'm actually doing this while I type this reply!"

* [https://community.endmyopia.org/t/an-easy-way-to-achieve-active-focus/6807 EM Forum thread where Mark Warren explains his theories on Active Focus]

== One unofficial analogy to think about the above techniques ==

... is that they are all combined to perform a human [https://en.wikipedia.org/wiki/Simultaneous_localization_and_mapping simultaneous localization and mapping], which is a concept normally utilized in the domain of robotics. For a robot to locate itself in an environment using a video camera, the robot needs to track the positions of various features it can recognize in its vision. Robots that are tracking their movement can use the relative movement between objects in a video image to estimate distance. "Stationary movement" is analogous to a robot rotating its camera and tracking the relative movement of objects in the camera image (to oversimplify, you can calculate the distances of the tracked objects by processing the geometry of the object movement combined with the known angle of rotation).

[https://www.youtube.com/watch?v=7Hlb8YX2-W8&t=35440s To illustrate the above concepts, here's a video timestamp of a programmer creating a 3D model of a world just from a 2D video.]

[[Category:Unicorn Farming]]

Myopia is Mental

2022-10-10T05:03:49Z

Snax: /* Criticism */

[https://www.myopiaismental.com/ Myopia is Mental]

[https://www.youtube.com/user/markhyo YouTube Channel]

'''Myopia is Mental''' is a vision improvement method created by Mark Warren.

Emphasizes noticing the relative movement of objects in [[peripheral vision]] as a way to relax the eye for clearer vision. Suggests that [[tunnel vision]] can cause people to not notice peripheral vision, keeping the eyes in a tensed state.

The method has existed since the start of 2020.

==Criticism==

Myopia is Mental has been criticized as lacking details on certain topics, such as how to handle complex glasses prescription ([https://www.myopiaismental.com/faqs There is an emphasis on significantly reduced or no correction.]). Emphasizes [[clear flashes]] as a signal for improvement, which may be hard to reproduce consistently across various individuals. It also ignores the scientific consensus that [[myopia]] is caused by a longer [[axial length]] of the eyeball, [https://www.youtube.com/watch?v=S0rXN4C-sKY by suggesting that the eye is squeezed by chronic tension]:

: I believe both. Tension is the enemy in both cases. Too much tension in the ciliary body makes the muscle stiff so now the lens can't move/focus. The lens can become hardened over time from lack of movement. Think about an engine that sits for a long period of time. It can eventually deadlock. As for eye elongation. I don't think the eyes grow long or rather grow at all. I believe the tension caused my the extraocular muscles squish the eyeball to make it long. Think about a round balloon and you use your hand to smash it down. It becomes long. Learn to relieve the tension in both the ciliary and extraocular muscles and you fix both!

There are other writings that indicate that MiM advocates that [https://www.myopiaismental.com/why-i-think-its-mental-and-why-i-started-mim/ myopia is more mental than physical]. This clashes with EM's view that myopia is related to the physical shape of the eye, and that any changes need to be measured and gradual to prevent issues with too much changes in the eye being too difficult for the brain to adapt to (which may manifest as double vision or eye discomfort).

MiM also encourages chasing a feeling of stinging or watering in the eyes while practicing active focus. EM strongly cautions against this attitude, instead recommending that any pain should be used as a hint to moderate any behavior. Rule of thumb for EM: If it hurts, you really should consider stopping what you are doing that is causing the pain.

Marks [https://community.endmyopia.org/t/an-easy-way-to-achieve-active-focus/6807 claims] to have improved from "Left -5.00 with a -1.00 / 80 axis for astigmatism and Right -4.0" to "-1.50 in both eyes" between the periods of November 2018 thru August 2019. This is considered very fast improvement by EM standards, and not considered a realistic improvement rate by both EM and mainstream optometry standards.

Do feel free to give it a go. Make your own mind up - be skeptical and avoid [[Blind belief]].

There's a minority contingent of EM participants who find the material interesting from the angle of learning about what to notice in peripheral vision.

==Habits, practices, and concepts suggested by Mark Warren==

* [https://www.youtube.com/watch?v=ccgw6WODV90 Tracking multiple objects in 3D space], to aid with "automatic focus" (Myopia is Mental's rephrasing of [[Active Focus]]). Specifically, noticing the relative movement of all objects in your awareness as you change your focus between objects at different distances while slowly moving your head position.

* "Rocking" exercise by moving one's body so that the head is moving side to side while the eyes are looking at various objects of interest. To be practiced with multi-object tracking above.

* [https://www.youtube.com/watch?v=RfO0x9uIkTQ Stationary movement] exercise by rotating one's head while tracking multiple objects at different ranges, and noticing that relative movement between objects changes with distance.

* Combining the practices of multi-object tracking and "stationary movement" by talking walks to see how objects move relative to each other as you move in different directions (either by turning in place, or by walking away/toward/past objects).

* Maintaining awareness of peripheral vision even when looking at objects in central vision. A specific technique Mark calls "peripheral triangulation" involves looking at a target object with your central vision, while noticing the positions and distances of objects in the peripheral awareness relative to the target object in view. One suggestion [https://www.youtube.com/watch?v=S0rXN4C-sKY mentioned in a video comments thread] is to turn on a muted TV as a peripheral vision background while looking at a central vision target:

: "A lot of people say the peripheral isn't important but I'm going to tell you why many have trouble seeing the full field of view while looking at something with their central vision. . If you spend a lot of times indoors in rooms, you're surrounded by stationary objects that don't move. This isn't natural! The only way for them to move is for "you" to move! If you think about being outside in nature, nothing is ever perfectly still! The wind blows ever so slightly and it will cause trees, plants and flowers to sway. Also you don't sit in square, confined boxes in nature (which is why it's easier to improve vision outdoors vs indoors). To improve your ability to see movement indoors try reading with a TV running in the background to your left or right. Turn the sound off so you're not distracted by it, but as you read notice the movement on the TV as you read. I'm actually doing this while I type this reply!"

* [https://community.endmyopia.org/t/an-easy-way-to-achieve-active-focus/6807 EM Forum thread where Mark Warren explains his theories on Active Focus]

== One unofficial analogy to think about the above techniques ==

... is that they are all combined to perform a human [https://en.wikipedia.org/wiki/Simultaneous_localization_and_mapping simultaneous localization and mapping], which is a concept normally utilized in the domain of robotics. For a robot to locate itself in an environment using a video camera, the robot needs to track the positions of various features it can recognize in its vision. Robots that are tracking their movement can use the relative movement between objects in a video image to estimate distance. "Stationary movement" is analogous to a robot rotating its camera and tracking the relative movement of objects in the camera image (to oversimplify, you can calculate the distances of the tracked objects by processing the geometry of the object movement combined with the known angle of rotation).

[https://www.youtube.com/watch?v=7Hlb8YX2-W8&t=35440s To illustrate the above concepts, here's a video timestamp of a programmer creating a 3D model of a world just from a 2D video.]

[[Category:Unicorn Farming]]

Myopia is Mental

2022-10-10T04:57:20Z

Snax: /* Criticism */

[https://www.myopiaismental.com/ Myopia is Mental]

[https://www.youtube.com/user/markhyo YouTube Channel]

'''Myopia is Mental''' is a vision improvement method created by Mark Warren.

Emphasizes noticing the relative movement of objects in [[peripheral vision]] as a way to relax the eye for clearer vision. Suggests that [[tunnel vision]] can cause people to not notice peripheral vision, keeping the eyes in a tensed state.

The method has existed since the start of 2020.

==Criticism==

Myopia is Mental has been criticized as lacking details on certain topics, such as how to handle complex glasses prescription ([https://www.myopiaismental.com/faqs There is an emphasis on significantly reduced or no correction.]). Emphasizes [[clear flashes]] as a signal for improvement, which may be hard to reproduce consistently across various individuals. It also ignores the scientific consensus that [[myopia]] is caused by a longer [[axial length]] of the eyeball, [https://www.youtube.com/watch?v=S0rXN4C-sKY by suggesting that the eye is squeezed by chronic tension]:

: I believe both. Tension is the enemy in both cases. Too much tension in the ciliary body makes the muscle stiff so now the lens can't move/focus. The lens can become hardened over time from lack of movement. Think about an engine that sits for a long period of time. It can eventually deadlock. As for eye elongation. I don't think the eyes grow long or rather grow at all. I believe the tension caused my the extraocular muscles squish the eyeball to make it long. Think about a round balloon and you use your hand to smash it down. It becomes long. Learn to relieve the tension in both the ciliary and extraocular muscles and you fix both!

There are other writings that indicate that MiM advocates that [https://www.myopiaismental.com/why-i-think-its-mental-and-why-i-started-mim/ myopia is more mental than physical]. This clashes with EM's view that myopia is related to the physical shape of the eye, and that any changes need to be measured and gradual to prevent issues with too much changes in the eye being too difficult for the brain to adapt to (which may manifest as double vision or eye discomfort).

MiM also encourages chasing a feeling of stinging or watering in the eyes while practicing active focus. EM strongly cautions against this attitude, instead recommending that any pain should be used as a hint to moderate any behavior. Rule of thumb for EM: If it hurts, you really should consider stopping what you are doing that is causing the pain.

Do feel free to give it a go. Make your own mind up - be skeptical and avoid [[Blind belief]].

There's a minority contingent of EM participants who find the material interesting from the angle of learning about what to notice in peripheral vision.

==Habits, practices, and concepts suggested by Mark Warren==

* [https://www.youtube.com/watch?v=ccgw6WODV90 Tracking multiple objects in 3D space], to aid with "automatic focus" (Myopia is Mental's rephrasing of [[Active Focus]]). Specifically, noticing the relative movement of all objects in your awareness as you change your focus between objects at different distances while slowly moving your head position.

* "Rocking" exercise by moving one's body so that the head is moving side to side while the eyes are looking at various objects of interest. To be practiced with multi-object tracking above.

* [https://www.youtube.com/watch?v=RfO0x9uIkTQ Stationary movement] exercise by rotating one's head while tracking multiple objects at different ranges, and noticing that relative movement between objects changes with distance.

* Combining the practices of multi-object tracking and "stationary movement" by talking walks to see how objects move relative to each other as you move in different directions (either by turning in place, or by walking away/toward/past objects).

* Maintaining awareness of peripheral vision even when looking at objects in central vision. A specific technique Mark calls "peripheral triangulation" involves looking at a target object with your central vision, while noticing the positions and distances of objects in the peripheral awareness relative to the target object in view. One suggestion [https://www.youtube.com/watch?v=S0rXN4C-sKY mentioned in a video comments thread] is to turn on a muted TV as a peripheral vision background while looking at a central vision target:

: "A lot of people say the peripheral isn't important but I'm going to tell you why many have trouble seeing the full field of view while looking at something with their central vision. . If you spend a lot of times indoors in rooms, you're surrounded by stationary objects that don't move. This isn't natural! The only way for them to move is for "you" to move! If you think about being outside in nature, nothing is ever perfectly still! The wind blows ever so slightly and it will cause trees, plants and flowers to sway. Also you don't sit in square, confined boxes in nature (which is why it's easier to improve vision outdoors vs indoors). To improve your ability to see movement indoors try reading with a TV running in the background to your left or right. Turn the sound off so you're not distracted by it, but as you read notice the movement on the TV as you read. I'm actually doing this while I type this reply!"

* [https://community.endmyopia.org/t/an-easy-way-to-achieve-active-focus/6807 EM Forum thread where Mark Warren explains his theories on Active Focus]

== One unofficial analogy to think about the above techniques ==

... is that they are all combined to perform a human [https://en.wikipedia.org/wiki/Simultaneous_localization_and_mapping simultaneous localization and mapping], which is a concept normally utilized in the domain of robotics. For a robot to locate itself in an environment using a video camera, the robot needs to track the positions of various features it can recognize in its vision. Robots that are tracking their movement can use the relative movement between objects in a video image to estimate distance. "Stationary movement" is analogous to a robot rotating its camera and tracking the relative movement of objects in the camera image (to oversimplify, you can calculate the distances of the tracked objects by processing the geometry of the object movement combined with the known angle of rotation).

[https://www.youtube.com/watch?v=7Hlb8YX2-W8&t=35440s To illustrate the above concepts, here's a video timestamp of a programmer creating a 3D model of a world just from a 2D video.]

[[Category:Unicorn Farming]]

Myopia is Mental

2022-10-10T04:54:48Z

Snax:

[https://www.myopiaismental.com/ Myopia is Mental]

[https://www.youtube.com/user/markhyo YouTube Channel]

'''Myopia is Mental''' is a vision improvement method created by Mark Warren.

Emphasizes noticing the relative movement of objects in [[peripheral vision]] as a way to relax the eye for clearer vision. Suggests that [[tunnel vision]] can cause people to not notice peripheral vision, keeping the eyes in a tensed state.

The method has existed since the start of 2020.

==Criticism==

Myopia is Mental has been criticized as lacking details on certain topics, such as how to handle complex glasses prescription ([https://www.myopiaismental.com/faqs There is an emphasis on significantly reduced or no correction.]). Emphasizes [[clear flashes]] as a signal for improvement, which may be hard to reproduce consistently across various individuals. It also ignores the scientific consensus that [[myopia]] is caused by a longer [[axial length]] of the eyeball, [https://www.youtube.com/watch?v=S0rXN4C-sKY by suggesting that the eye is squeezed by chronic tension]:

: I believe both. Tension is the enemy in both cases. Too much tension in the ciliary body makes the muscle stiff so now the lens can't move/focus. The lens can become hardened over time from lack of movement. Think about an engine that sits for a long period of time. It can eventually deadlock. As for eye elongation. I don't think the eyes grow long or rather grow at all. I believe the tension caused my the extraocular muscles squish the eyeball to make it long. Think about a round balloon and you use your hand to smash it down. It becomes long. Learn to relieve the tension in both the ciliary and extraocular muscles and you fix both!

There are other writings that indicate that MiM advocates that [https://www.myopiaismental.com/why-i-think-its-mental-and-why-i-started-mim/ myopia is more mental than physical]. This clashes with EM's view that myopia is related to the physical shape of the eye, and that any changes need to be measured and gradual to prevent issues with too much changes in the eye being too difficult for the brain to adapt to (which may manifest as double vision or eye discomfort).

Do feel free to give it a go. Make your own mind up - be skeptical and avoid [[Blind belief]].

There's a minority contingent of EM participants who find the material interesting from the angle of learning about what to notice in peripheral vision.

==Habits, practices, and concepts suggested by Mark Warren==

* [https://www.youtube.com/watch?v=ccgw6WODV90 Tracking multiple objects in 3D space], to aid with "automatic focus" (Myopia is Mental's rephrasing of [[Active Focus]]). Specifically, noticing the relative movement of all objects in your awareness as you change your focus between objects at different distances while slowly moving your head position.

* "Rocking" exercise by moving one's body so that the head is moving side to side while the eyes are looking at various objects of interest. To be practiced with multi-object tracking above.

* [https://www.youtube.com/watch?v=RfO0x9uIkTQ Stationary movement] exercise by rotating one's head while tracking multiple objects at different ranges, and noticing that relative movement between objects changes with distance.

* Combining the practices of multi-object tracking and "stationary movement" by talking walks to see how objects move relative to each other as you move in different directions (either by turning in place, or by walking away/toward/past objects).

* Maintaining awareness of peripheral vision even when looking at objects in central vision. A specific technique Mark calls "peripheral triangulation" involves looking at a target object with your central vision, while noticing the positions and distances of objects in the peripheral awareness relative to the target object in view. One suggestion [https://www.youtube.com/watch?v=S0rXN4C-sKY mentioned in a video comments thread] is to turn on a muted TV as a peripheral vision background while looking at a central vision target:

: "A lot of people say the peripheral isn't important but I'm going to tell you why many have trouble seeing the full field of view while looking at something with their central vision. . If you spend a lot of times indoors in rooms, you're surrounded by stationary objects that don't move. This isn't natural! The only way for them to move is for "you" to move! If you think about being outside in nature, nothing is ever perfectly still! The wind blows ever so slightly and it will cause trees, plants and flowers to sway. Also you don't sit in square, confined boxes in nature (which is why it's easier to improve vision outdoors vs indoors). To improve your ability to see movement indoors try reading with a TV running in the background to your left or right. Turn the sound off so you're not distracted by it, but as you read notice the movement on the TV as you read. I'm actually doing this while I type this reply!"

* [https://community.endmyopia.org/t/an-easy-way-to-achieve-active-focus/6807 EM Forum thread where Mark Warren explains his theories on Active Focus]

== One unofficial analogy to think about the above techniques ==

... is that they are all combined to perform a human [https://en.wikipedia.org/wiki/Simultaneous_localization_and_mapping simultaneous localization and mapping], which is a concept normally utilized in the domain of robotics. For a robot to locate itself in an environment using a video camera, the robot needs to track the positions of various features it can recognize in its vision. Robots that are tracking their movement can use the relative movement between objects in a video image to estimate distance. "Stationary movement" is analogous to a robot rotating its camera and tracking the relative movement of objects in the camera image (to oversimplify, you can calculate the distances of the tracked objects by processing the geometry of the object movement combined with the known angle of rotation).

[https://www.youtube.com/watch?v=7Hlb8YX2-W8&t=35440s To illustrate the above concepts, here's a video timestamp of a programmer creating a 3D model of a world just from a 2D video.]

[[Category:Unicorn Farming]]

Review:EyeBuyDirect

2022-09-24T06:05:38Z

Snax:

* [https://www.eyebuydirect.com/ Eye Buy Direct Company Site]
* [https://en.wikipedia.org/wiki/EyeBuyDirect Eye Buy Direct Wikipedia Entry]

[[Category:Glasses Seller]]

The following points may vary between different customer experiences:

* In the USA, the finalized frames + lenses are shipped from an address in St. Louis, Missouri. Shipping times may contrast with Zenni, where Zenni's eyeglasses may take longer to ship overseas from their China facilities.
* It is normal for orders to take a very long time during "Lens Cutting & Bevel edging". [On Reddit, it's been suggested that sometimes an order may need to be redone, so that may explain why this stage of an order may take a longer time that usual (as long as 2 weeks versus the usual 1 week, for example). [https://www.reddit.com/r/glasses/comments/h9td9q/eyebuydirect_lenses_cutting_and_bevel_edging/ Reddit discussion]
* EBD may invalidate your coupons earlier than their expiration dates for any reason, without warning. Reasons include anniversary dates (from signup) which resets loyalty program progress, your loyalty program tier a.k.a. "Focus Rewards" changes (which invalidates your coupons associated with the previous loyalty tier), or that they simply changed how a promotion program worked, etc. If you have a coupon code, you should expect that it can be invalidated sooner than the written expiration date. Coupon offers are not real until you redeem them.
* At the time of edit, EBD does not offer 1.57 index lenses. If you have a moderate prescription, you may want to go with a lens seller that offers 1.57 index for cost reasons.
* EBD sells MR 1.6, in contrast to Zenni which sells MR 1.61. MR 1.61 has slightly better clarity and is slightly lighter than MR 1.6.

Chromatic Aberration

2022-09-18T04:49:10Z

Snax: /* Lens Material */

Chromatic aberration is probably most easily understood as a prism effect. When light shines through a prism, you see that different colors of light bend (undergo [[Refraction]]) differently and create a rainbow effect. When light shines through any lens, including glasses and the natural lens of your eye, the same occurs to a lesser degree. The effect of this is that the [[Focal Length]] of the lens is not exactly the same for all colors of light.

[[File:Chromatic aberration lens diagram.svg|Chromatic aberration lens diagram]]

== Duochrome test ==
{| class="wikitable"
|-
! style="background-color:green;font-size: 150%" | KH
! style="background-color:red;font-size: 150%" | HK
|-
! style="background-color:green" | EPO
! style="background-color:red" | OPE
|}

The chromatic aberration expected during a normal eye exam is about a half diopter difference between red and green. This can be a handy test to dial in a final prescription by looking at text on red and green backgrounds and seeing which is clearer.

<youtube>WP6eeoyB9go</youtube>

== External Sources ==
* [[Wikipedia:Chromatic aberration]]
* [[Wikipedia:Duochrome test]]

== Lens Material ==
Different materials have different [https://en.wikipedia.org/wiki/Abbe_number Abbe numbers]. Materials with higher values are better, since they tend to have less chromatic aberration.

Here are some typical values:<ref>https://www.allentownoptical.com/abbe-value-interpretation/</ref>

{| class="wikitable sortable"
!Material
!Index
!Abbe Value
|-
|Crown Glass
|1.523
|59
|-
|High Index Glass
|1.60
|42
|-
|High Index Glass
|1.70
|39
|-
|Plastic CR-39
|1.49
|58
|-
|Mid Index Plastic
|1.54
|47
|-
|Mid Index Plastic
|1.56
|36
|-
|High Index Plastic
|1.60
|36
|-
|High Index Plastic
|1.66
|32
|-
|Trivex
|1.53
|43
|-
|Polycarbonate
|1.58
|30
|-
|MR-174
|1.74
|32
|}

[[File:Lens materials and optical quality chart.png|Lens materials and optical quality chart]]

[https://community.endmyopia.org/t/lens-materials-and-optical-quality-chart/4415 chart created by steadicat]

=== Tradeoff Between Chromatic Aberration vs Distortion ===

When choosing lens index, remember to take into account overall distortion at the edges of the lens. Too much overall distortion may make it difficult to view the edges of the lenses.

[https://endmyopia.org/need-high-index-lenses/ EndMyopia: Do You Need High Index Lenses?]

The following vendor articles may be of interest:
* [https://www.zennioptical.com/glasses-lenses Zenni]
* [https://www.eyebuydirect.com/prescription-lens/lens-index EyeBuyDirect]
* [https://www.selectspecs.com/guides/lenses/single-vision/ SelectSpecs]
* [https://www.framesbuy.com/trends/lens-index/ FramesBuy]

Anecdotally from the forums, -3 is a balanced cutoff range for CR-39 where one can take advantage of higher abbe and competitive cost, without experiencing too much distortion at lens edges. Outside of that range, consider higher index lenses to minimize distortion.

==References==
{{reflist}}

[[Category:Articles]]

Chromatic Aberration

2022-09-18T04:47:01Z

Snax: /* Lens Material */

Chromatic aberration is probably most easily understood as a prism effect. When light shines through a prism, you see that different colors of light bend (undergo [[Refraction]]) differently and create a rainbow effect. When light shines through any lens, including glasses and the natural lens of your eye, the same occurs to a lesser degree. The effect of this is that the [[Focal Length]] of the lens is not exactly the same for all colors of light.

[[File:Chromatic aberration lens diagram.svg|Chromatic aberration lens diagram]]

== Duochrome test ==
{| class="wikitable"
|-
! style="background-color:green;font-size: 150%" | KH
! style="background-color:red;font-size: 150%" | HK
|-
! style="background-color:green" | EPO
! style="background-color:red" | OPE
|}

The chromatic aberration expected during a normal eye exam is about a half diopter difference between red and green. This can be a handy test to dial in a final prescription by looking at text on red and green backgrounds and seeing which is clearer.

<youtube>WP6eeoyB9go</youtube>

== External Sources ==
* [[Wikipedia:Chromatic aberration]]
* [[Wikipedia:Duochrome test]]

== Lens Material ==
Different materials have different [https://en.wikipedia.org/wiki/Abbe_number Abbe numbers]. Materials with higher values are better, since they tend to have less chromatic aberration.

Here are some typical values:<ref>https://www.allentownoptical.com/abbe-value-interpretation/</ref>

{| class="wikitable sortable"
!Material
!Index
!Abbe Value
|-
|Crown Glass
|1.523
|59
|-
|High Index Glass
|1.60
|42
|-
|High Index Glass
|1.70
|39
|-
|Plastic CR-39
|1.49
|58
|-
|Mid Index Plastic
|1.54
|47
|-
|Mid Index Plastic
|1.56
|36
|-
|High Index Plastic
|1.60
|36
|-
|High Index Plastic
|1.66
|32
|-
|Trivex
|1.53
|43
|-
|Polycarbonate
|1.58
|30
|-
|MR-174
|1.74
|32
|}

[[File:Lens materials and optical quality chart.png|Lens materials and optical quality chart]]

[https://community.endmyopia.org/t/lens-materials-and-optical-quality-chart/4415 chart created by steadicat]

=== Tradeoff Between Chromatic Aberration vs Distortion ===

When choosing lens index, remember to take into account overall distortion at the edges of the lens. Too much overall distortion may make it difficult to view the edges of the lenses.

[https://endmyopia.org/need-high-index-lenses/ EndMyopia: Do You Need High Index Lenses?]

The following vendor articles may be of interest:
* [https://www.zennioptical.com/glasses-lenses Zenni]
* [https://www.eyebuydirect.com/prescription-lens/lens-index EyeBuyDirect]
* [https://www.selectspecs.com/guides/lenses/single-vision/ SelectSpecs]
* [https://www.framesbuy.com/trends/lens-index/ FramesBuy]

Anecdotally from the forums, -3 is a balanced cutoff range for CR-39 where one can take advantage of higher abbe and competitive cost, without experience too much distortion at lens edges.

==References==
{{reflist}}

[[Category:Articles]]

Review:EyeBuyDirect

2022-09-05T23:33:58Z

Snax:

Review:EyeBuyDirect

2022-09-05T23:33:27Z

Snax:

* [https://www.eyebuydirect.com/ Eye Buy Direct Company Site]
* [https://en.wikipedia.org/wiki/EyeBuyDirect Eye Buy Direct Wikipedia Entry]

[[Category:Glasses Seller]]

The following points may vary between different customer experiences:

* In the USA, the finalized frames + lenses are shipped from an address in St. Louis Missouri. Shipping times may contrast with Zenni, where Zenni's eyeglasses may take longer to ship overseas from their China facilities.
* It is normal for orders to take a very long time during "Lens Cutting & Bevel edging". [On Reddit, it's been suggested that sometimes an order may need to be redone, so that may explain why this stage of an order may take a longer time that usual (as long as 2 weeks versus the usual 1 week, for example). [https://www.reddit.com/r/glasses/comments/h9td9q/eyebuydirect_lenses_cutting_and_bevel_edging/ Reddit discussion]
* EBD may invalidate your coupons earlier than their expiration dates for any reason, without warning. Reasons include anniversary dates (from signup) which resets loyalty program progress, your loyalty program tier a.k.a. "Focus Rewards" changes (which invalidates your coupons associated with the previous loyalty tier), or that they simply changed how a promotion program worked, etc. If you have a coupon code, you should expect that it can be invalidated sooner than the written expiration date. Coupon offers are not real until you redeem them.

Eye strain

2022-08-22T03:39:48Z

Snax: /* Distance Vision Strain */

'''Eye strain''', or '''asthenopia''', is fatigue of the ciliary muscles and extraocular muscles. Eye strain does not cause [[myopia]], but it can lead to [[pseudomyopia]]. Eye strain can lead to discomfort, including soreness and redness. As a rule the goal of [[EndMyopia]] is to use stimulus without causing unnecessary strain.

==The over-worked muscles==
The ciliary muscles control focus by changing the shape of the lens. Looking at near objects for extended periods of time strains the ciliary muscle, leading to a [[ciliary spasm]]. This muscle is most relaxed when looking far in the distance.

Extraocular muscles control the movement of the eye and the eyelid. These muscles may tighten during intense visual work or when the body perceives a threat. When tightened, a person may appear to be scowling or squinting. Closing the eyes and massaging around the eye can temporarily relax these muscles, but they will quickly tighten again if the core problem is not addressed with better habits. In addition to causing discomfort, strained extraocular muscles will result in a wrinkly, unpleasant facial expression.

==Causes and solutions==
[[Blur]] from uncorrected vision, or severely under corrected vision, causes eye strain. This problem is solved by wearing the [[differential]] or [[normalized]] lenses that are most appropriate for the situation and distance. Good ambient lighting will also go a long way to help avoid eye strain. More light means better vision, and natural light is the best light.

Staring at a computer monitor or other electronic screen for extended periods of time may cause eye strain under certain conditions:
* '''The screen contrasts with the environment'''. The color temperature and brightness of the screen should be adjusted to match the surrounding environment. Or, the lighting in the room may need to be adjusted to better match the screen. Having the lights off in the room while staring at a screen is never a good idea.
* '''The screen is too close to eyes'''. The screen should be at least an arm's length away from the eyes. With tiny phone screens, this is impractical; the bad habit of doing everything on the phone should be replaced with a good habit of doing as much as possible on a desktop or laptop computer at a healthy distance from the eyes. If you use a smartphone, consider replacing it with a feature phone.
* '''The staring is being done without reasonable breaks'''. At the very least, the eyes should be given a short break every 20 minutes and a long break every 60 minutes.
* '''The screen is low-quality or uses old technology'''. The old CRT technology is rarely used now, but be aware that its inherent flicker strains the eyes. The human eye certainly struggles when viewing light that flickers on and off 60 times per second! Unfortunately, even the current display technology, LCD, can flicker. Low-quality LCDs use PWM dimming, where the backlight is switched on and off hundreds of times per second. High-quality LCDs are designed with DC dimming, where the light is constant.

==Distance Vision Strain==
Some participants report feeling strain after long sessions of distance active focus.
One suggestion for handling distance strain is to balance both near and far accommodation, which is referred sometimes as "dynamic vision" activity.
Different theories which are still in contention were proposed to describe the mechanism of accommodation. Some of those theories are:

'''Helmholtz theory of accommodation (1855)'''– This theory is also called the capsular theory of accommodation . Helmholtz theorized that when the eyes are viewing a distant object, the ciliary muscle relaxes and the zonular fibers between the ciliary body 1 and the equator of the lens stay flattened but when the object of focus is close, the ciliary muscles contract and the zonular fibers loosen. In the Helmholtz theory, the lens equator slides away from the sclera during accommodation and closer to the sclera when accommodation ends. In this theory, the zonular fibers are relaxed during accommodation and the zonular fibers are under tension when there is no accommodation reflex.

'''Schacher theory of accommodation (2006)'''- This theory states that when the lens is in focus, there is increased tension on the lens through the equatorial zonular fibers and when there is contraction of the ciliary muscle, the zonular fibers located equatorially increase their tensile strength. This results in the steepness of the central surface of the lens, an increase in thickness of the lens and a flattening of the lens edges. As the tension on the equatorial zonular fibers increase during accommodation, the anterior and posterior zonular fibers relax. The anterior and posterior zonular fibers serve as passive support structures for the lens, but the equatorial zonular fibers determines the refractive power of the lens.

Possibly related to: Theory of Reciprocal Zonular Action:
https://www.youtube.com/watch?v=1yIpyitm6eE

'''Catenary theory of accommodation (1970)'''– This theory is also called the Coleman theory of accommodation. It states that the lens and the zonula fibers form a diaphragm, which is held in a catenary (a curve formed by a wire, rope, or chain hanging freely from two points that are not in the same vertical line) shape due to the difference in pressure between the aqueous and vitreous bodies of the lens. A change in diameter of the ciliary body results in a change of the catenary shape. It means there is a continuous pressure difference on the lens. The strength of this pressure difference is approximately 2.3 cm of water column, with major changes occurring during the initial seconds of the accommodation phase. The anterior capsule and the zonular fibers form hammock shaped surface that is duplicable but depends on the diameter of the ciliary body. The ciliary body however makes a shape like the pillars of a suspension bridge, but does not need to support the force around the equator to flatten the lens.

[https://community.endmyopia.org/t/distance-vision-strain/17674 forum discussion on distance strain]

==References==
{{reflist}}

[[Category:Articles]]
[[Category:Eye conditions]]

File:Lens materials and optical quality chart.png

2022-08-05T07:12:20Z

Snax: /* Summary */

== Summary ==
Lens materials and optical quality chart

from: https://community.endmyopia.org/t/lens-materials-and-optical-quality-chart/4415

Chromatic Aberration

2022-08-05T07:08:54Z

Snax:

File:Lens materials and optical quality chart.png

2022-08-05T07:07:29Z

Snax: Lens materials and optical quality chart

== Summary ==
Lens materials and optical quality chart

Huberman

2022-08-03T16:37:10Z

Snax: /* Recommended Vision Practices */added interview clip of Huberman discussing panoramic vision

Some EM participants are also huge nerds for the [https://hubermanlab.com/ Huberman Lab Podcast]

'''[https://hubermanlab.com/the-science-of-vision-eye-health-and-seeing-better/ Podcast episode on vision]'''

==Recommended Vision Practices==
* View sunlight by going outside within 30-60 minutes of waking. Do that again in the late afternoon, prior to sunset.
* Get outdoor exposure for at least 2 hours a day
* For every 90 minutes of [[Close-up|close-up]] vision, take a 20+ minute [[Distance vision|distance]] viewing break
* Self directed movement like walking or cycling is beneficial. This may be related to [https://en.wikipedia.org/wiki/Eye_movement_desensitization_and_reprocessing EMDR] where eye movement from left to right can help with processing thoughts. The [[eyeballs|ciliary]] muscle can also relax as you notice objects passing in and out of your vision as you move forwards.
* Tilting your eyes in your eye sockets upwards can make you more alert. You could take advantage of this by placing something to look at higher than your head level.
* Myopia has an observed correlation with not sleeping in a dark room.
* Make time for distance viewing every day.
* You can train your vision by tracking smoothly moving objects. aka "smooth pursuit"
* You can train near-far visual training, 2-3 minutes, 3-4 times a week
* Exposure to red light early in the day has shown promise in improving vision in adults 40+ years in age.
* Is also a proponent of printing out a [[Snellen]] chart and experimenting with it.

(editor's note: just listen to the episode...)

Clip about panoramic vision:
https://www.youtube.com/watch?v=dqCEOJSvgwA

==Recommended Sleep Practices==

(From the sleep recommendations newsletter:)[https://hubermanlab.com/toolkit-for-sleep/]
* View sunlight by going outside within 30-60 minutes of waking. Do that again in the late afternoon, prior to sunset. Ideally without [[sunglasses]], but don't look at light so bright that you need to squint.
* Avoid viewing bright lights—especially bright overhead lights between 10 pm and 4 am.

[https://hubermanlab.com/dr-samer-hattar-timing-light-food-exercise-for-better-sleep-energy-mood/ Interview with Dr. Samer Hattar:]
* Dr. Hattar's opinion that color spectrum changing glasses like blue-blocker glasses [https://www.youtube.com/watch?v=oUu3f0ETMJQ&t=2695s are not a good idea]
* TODO: someone listen to the episode again and let us know your takeaways in here.

User:Angel

2022-08-01T19:33:47Z

Snax: /* Leave a message */left a message

==Anticipated Glasses Future==
===Next glasses ===

====normal/normalized glasses will be brown frames====

OD/Right: -4.00 sphere, -1.50 cylinder, 171 axis

OS/Left: -3.75 sphere, -1.75 cylinder, 176 axis

Lens: 1.57 Mid-Index

====closeup/differential glasses will be gold frames====
OD/Right: -3.00 sphere, -1.50 cylinder, 171 axis

OS/Left: -2.75 sphere, -1.75 cylinder, 176 axis

Lens: 1.57 Mid-Index

==My Glasses History==

I figured I should track this somewhere and maybe someday I will make enough progress that this level of detail will be interesting to someone besides me. Or maybe just knowing my context is useful. Also adding other non-glasses stuff that could be relevant.

===July2022===

====Bike trip ends====

Using borrowed tv screen as monitor. Quit all refined sugar again.

====Bike trip review====

Didn't make any changes while bicycling. Rode my bike a bunch, used the laptop a bunch. Got a bit of a tan. Ate a TON of junk food. ALLLlll the sugary things. Traveled maybe 2,000 miles.

===March 2022===

====Bicycle trip starts====

This is when I left on a bicycle trip. I'm getting lots of sunshine and outdoor time. This is a dramatic change from my winter habits this year, so I won't make any changes to my glasses at this time.

Abandoned keyboard and mouse, no room to pack 'em.
===January 26, 2022===

====Found a free keyboard and mouse.====

Now I can get my laptop further away from my lap. Only problem is, I just switched to new normalized glasses a few days ago! So I am concerned about effectively changing two focal planes at once. Oh well. Will try to be conservative about where I set my computer, while still getting in the habit of using the keyboard and mouse.

In short, I have to be cautious about not effectively changing two focal planes at once.
===January 22, 2022===
====normal glasses - black frames====
OD/right: -4.25 sphere, -1.5 cylinder, 171 axis

OS/left: -4 sphere, -1.75 cylinder, 176 axis

Lens: 1.57 Mid-Index

=== November 7, 2021===
====Normal glasses====

Couldn't find my original prescription when I wanted to change glasses from my close-ups (differentials) so I decided it was time to switch to my first normalized glasses. It feels like it has been about a month. I also received my over-the-glasses sunglasses yesterday!

:OD/Right -4.50 sphere, -1.50 cylinder, 171 axis

:OS/Left -4.25 sphere,-1.75 cylinder, 176 axis
Lens: 1.57 Mid-Index
===Mid-October 2021===
====[https://wiki.endmyopia.org/wiki/Differentials Close-ups] - blue frames====
:OD/Right: -3.25 sphere, -1.5 cylinder, 171 axis

:OS/Left: -3 sphere, -1.75 cylinder, 176 axis

:Zenni frame 411516 because it's got half a dozen colors so I can keep track of new glasses easier, and it's the cheapest metal frames they sell. These frames are blue.
Lens: 1.57 Mid-Index

===Mid-September 2021===

====End Myopia discovery====
: Found endmyopia.org somewhere. I had been looking for wrap-around sunglasses that would work with my prescription, which was apparently not in "cheap sunglasses on Zenni" territory.

====Eating more fiber====
: Figured out I can get most of my vitamins and minerals from 2 cups cooked greens and a can of beans every day. My fiber intake just went up dramatically and permanently.

===July 2021===
====Prescription====
:Right: -4.75 sphere, -1.5 cylinder, 171 axis

:Left: -4.5 sphere, -1.75 cylinder, 176 axis

===January(ish) 2020===

====Checkup====
:Talked optometrist into just checking eye health. Eye health was fine.
===June 2019===

====Quit refined sugar====

:Did someone refine the fiber out? I won't eat it. Juice? Unacceptable. Honey? Refined by bees. Maple syrup? Sure, if I'm gnawing on a maple tree. Cane sugar? Sure, if I'm eating the cane alone with it. And so forth.

:NOTE: This took me 20 years of effort before it finally stuck. If at first you don't succeed, try, try, and try again. I get refined sugar on my birthdays.

===July 2018===
====Prescription====
:OD: -5 sphere, -1.5 cylinder, 175 axis

:OS: -4.5 sphere, -1.75 cylinder, 175 axis
1.61 Blokz Photochromic - Gray

===May 2011===

====Prescription====
:OD: -5 sphere, -1.5 cylinder, 168 axis

:OS: -4.5 sphere, -1.75 cylinder, 175 axis
===Early 1990s===

Kept forgetting my glasses at home and not being able to see the blackboard clearly from the first row. Annoyed teacher told me I needed to start remembering to bring my glasses. This is when I started wearing glasses full time.

===Late 1980s===

'''I was warned.''' When I was given my first pair of glasses, I was told, repeatedly, ''don't wear these glasses when you don't need them.'' I was living in England at the time. Not sure if it was an English doctor or a US military doctor. In my medical records, my early glasses are "for distance only".

==Why I'm here==

People with low-to-no myopia are less prone to retinal detachment. Eye problems run in my family. I figure I should do what I can to keep my eyesight in working order.

Things I'd like to be able to see clearly without glasses again:
* the stars

* my toes

==My friends on the Wiki (add yourself!)==

[[User:Kg6gfq|Kg6gfq]]

==Leave a message ==
You won't find me on the EndMyopia forum. But you can leave me an eyeballs-related message here!

Glad you had a good trip! -snax 8/1/22

Guide:Reducing lens complexity

2022-07-04T18:42:29Z

Snax: /* When to reduce lens complexity */

TODO: this article needs to be expanded for edge cases like already low diopters.

==When to reduce lens complexity==

[[Lens complexity]] is best reduced before getting into the [[low diopters]] range. Ideally, normalized correction for both eyes should be simple and equal by the time a low diopters range (e.g. -1.5 [[diopters]])<ref>https://endmyopia.org/pro-topic-nick-is-time-to-equalize-diopters/</ref> is reached.

==How to reduce lens complexity==

'''Make your first reduction or two simple and [[spherical]]. This will teach you the basics of the [[EndMyopia]] methods.'''

There are two types of reductions:

* <div>A ''simple reduction'' or ''binocular reduction'' is drop in lens powers for both eyes, simultaneously</div>
* <div>An ''equalizing reduction'' or ''monocular reduction'' is drop in lens power for one eye, the eye with greater correction (more negative)</div>

An [[equalizing]] reduction is done to bring the eyes closer to having the same level of correction. Jake said that "...if you do reduce the ratio, you should have at least 2 regular spherical reductions in between."<ref>https://community.endmyopia.org/t/key-to-patching-successfully-reducing-diopter-ratio/333/6</ref> This is not always possible, especially when [[Guide:High diopter gap|high anisometropia]] is involved.

There are three types of reductions with respect to the power change:
* a 0.25 [[diopter|D]] drop to [[spherical]] power
* a 0.25 D drop to [[cylindrical]] power
* a trade of 0.5 D cylindrical power for 0.25 D spherical power

'''There are four rules for reducing complexity:'''
# <div>Alternate types of reductions. Have one (Simple > Equalizing > Simple > Equalizing...) or two (Simple > Simple > Equalizing > Simple > Simple > Equalizing...) simple drops between equalizing drops.</div>
# <div>Change only spherical or only cylindrical and never both simultaneously.</div>
# <div>For an equalizing reduction, change both differential lenses and normalized lenses simultaneously to keep the [[focal planes]] in sync.<ref>https://endmyopia.org/the-diopter-ratio-trap-dont-favor-one-eye/</ref></div>
# <div>For a simple reduction, change differential lenses a few weeks after normalized lenses to keep changes to [[focal planes]] to a minimum.</div>

'''A note on rule 3 and rule 4:''' Keeping focal planes in sync is a higher priority than keeping changes to focal planes to a minimum, thus rule 3 exists.

{| class="wikitable" style="text-align:center;"
|+ Example Spherical Reduction Schedule
|-
! style="text-align:left;" | Reduction Type
! colspan="2" | Normalized
! colspan="2" | Differentials
! style="text-align:left;" | Explanation
|-
| style="text-align:left;" |
| Left
| Right
| Left
| Right
| style="text-align:left;" |
|-
| rowspan="2" style="text-align:left;" |
| -3.50
| -4.00
| -2.25
| -2.75
| style="text-align:left;" | This is the '''starting point'''.
|- style="text-align:left;"
| colspan="4" style="text-align:center;" | wait 8 - 16 weeks
|
|-
| rowspan="4" | Simple
| -3.25
| -3.75
|
|
| style="text-align:left;" | Perform normalized reduction.
|- style="text-align:left;"
| colspan="4" style="text-align:center;" | wait 4 - 8 weeks
| (rule 4)
|-
|
|
| -2.00
| -2.50
| style="text-align:left;" | Perform differential reduction.
|- style="text-align:left;"
| colspan="4" style="text-align:center;" | wait 4 - 8 weeks
|
|- style="font-weight:bold;"
| rowspan="2" | Equalizing
| -3.25
| -3.50
| -2.00
| -2.25
| style="text-align:left;" | Both norms and diffs are reduced simultaneously. (rule 3)
|- style="text-align:left;"
| colspan="4" style="text-align:center; font-weight:bold;" | wait 8 - 16 weeks
|
|-
| rowspan="4" | Simple
| -3.00
| -3.25
|
|
| style="text-align:left;" | Perform normalized reduction.
|- style="text-align:left;"
| colspan="4" style="text-align:center;" | wait 4 - 8 weeks
| (rule 4)
|-
|
|
| -1.75
| -2.00
| style="text-align:left;" | Perform differential reduction.
|- style="text-align:left;"
| colspan="4" style="text-align:center;" | wait 4 - 8 weeks
|
|- style="font-weight:bold;"
| rowspan="2" | Equalizing
| -3.00
| -3.00
| -1.75
| -1.75
| style="text-align:left;" | Both norms and diffs are reduced simultaneously. (rule 3)
|- style="text-align:left;"
| colspan="4" style="text-align:center; font-weight:bold;" | wait 8 - 16 weeks
|
|}

==References==
{{reflist}}

==See also==
* [[Equalizing]]

* [[Guide:Resolving double vision | Resolving double vision]]

* [[reduction | Reduction]]

[[Category:Guides]]