Difference between revisions of Frequently Asked Questions/Glasses

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==Buying glasses==
==Buying glasses==
====Where should I buy glasses online?====
====Where should I buy glasses online?====
See [[Review:Buying_glasses_and_lenses|buying glasses and lenses]].
See [[:Category:Lens seller]].
 
Blog post: [https://endmyopia.org/best-place-buy-glasses-online/ Where Is The Best Place To Buy Glasses Online?]
 
====How do I measure pupillary distance?====
====How do I measure pupillary distance?====
[[Zenni Optical]] has a great article on this. [https://www.zennioptical.com/measuring-pd-infographic Find that here]
[[Zenni Optical]] has a great article on this. [https://www.zennioptical.com/measuring-pd-infographic Find that here]
====Are polycarbonate lenses bad for your eyes?====
====Are polycarbonate lenses bad for your eyes?====
The fact that they are polycarbonate makes no difference to your eyes.
The fact that they are polycarbonate makes no difference to your eyes.
Blog post: [https://endmyopia.org/eye-uses-chromatic-aberration-to-guide-axial-change/ Polycarbonate Lenses – Bad For Your Eyes?]
==How do I read my prescription?==
See the [[Guide:Reading_glasses_prescriptions|Wiki guide to reading glasses prescriptions]]
==How do I measure my PD? (pupillary distance)==
{{main|Pupillary distance}}
Blog post: [https://endmyopia.org/how-to-measure-pd-pupillary-distance/ Headaches & Fatigue: Measure Your Pupillary Distance (PD)]
==Why are my glasses giving me a headache?==
==Why are my glasses giving me a headache?==
When myopia increases, people's headaches tend to get worse. This is largely due to the shrinking field of view higher [[diopter]] correction gives. There's a huge amount of variation in general in this area. It's safe to say though, the higher your diopters, the worse the headaches.
When myopia increases, people's headaches tend to get worse. This is largely due to the shrinking field of view higher [[diopter]] correction gives. There's a huge amount of variation in general in this area. It's safe to say though, the higher your diopters, the worse the headaches.
{{jake says|Short answer:  You have the wrong prescription!
But, you say, the optometrist says I’ll get used to it.  Still, your headache isn’t imaginary, and you didn’t have it before you put on those glasses.  What does that tell us?  The optometrist is, simply, wrong!
I’ll show you how you can measure your own eyesight, and explain exactly what causes the headaches, in this post:  https://endmyopia.org/headaches-because-of-glasses-the-fix-might-be-simple/}}
==My glasses are too thick and heavy, what do do?==
You probably have high or severe myopia. See the [[severe myopia]] page for guidance on selecting lighter-weight glasses.
==Test lens kits==
==Test lens kits==
===Do I need a test lens kit?===
===Do I need a test lens kit?===
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[[File:Trial test lens kit.jpg|right]]
[[File:Trial test lens kit.jpg|right]]
You insert the lenses from the kit into the really dorky-looking glasses. This way you can test different lenses and how they work.
You insert the lenses from the kit into the really dorky-looking glasses. This way you can test different lenses and how they work.
You can find optometrist approved guides on how to use a test lens kit [https://www.youtube.com/results?search_query=subjective+refraction+ian+squire here].
{{clear}}
{{clear}}
===Where can I buy an optometrist test lens kit?===
===Where can I buy an optometrist test lens kit?===
{{jake says|If you want to check your prescription strength needs at home, you probably want a test lens kit.  While this isn’t completely necessary for most people, you might opt to invest in a test lens kit for yourself.
There are a lot of places to buy test lens kits.  They range from a few hundred dollars to thousands, depending on the quality and the sales outlet.
Here is an article on what to look out for, and suggestions on where to look for kits as cheap as USD100:  https://endmyopia.org/where-to-buy-a-test-lens-kit/}}
==Plus lenses==
==Plus lenses==
===How do plus lenses work?===
===How do plus lenses work?===
{{main article|Plus lenses}}
{{main article|Plus lenses}}
Plus lenses make you '''more short-sighted, not less'''. They are for the most part useless when it comes to improving [[myopia]].
Plus lenses make you '''more short-sighted, not less'''. They are for the most part useless when it comes to improving [[myopia]].
===Should I use plus lenses to improve eyesight?===
{{jake says|I have mixed opinions about the use of plus lenses.  A recent forum reply sums them up fairly well:
I’m not a huge proponent of plus in general. For kids and prevention, yes. For professionals who need insane distance vision, yes. For those who need a lot of stimulus to make progress, yes.
Generally, for the large majority of myopes, with the standard lifestyle (lots of close-up at work, not much outdoor time, a lot of playing on smartphones and TV), not so much. If you’re just looking for 20/20, not needing glasses in generally all conditions, it’s just not a necessary component in a lot of cases.
He says, adjusting his plus lenses while writing this post.  ?
Plus is one of those things that’s got as many downsides as potential benefits. If you’re headed towards presbyopia, plus is risky business. You might substitute plus close-up for an extra hour of outdoor time, the latter of which would be more beneficial and give you better than equal results compared to plus use. But knowing you can just grab plus and work another hour, I’m not the biggest fan of. It’s also more lenses, which I generally like to get away from when there are natural focal plane alternatives. The whole thing of where we love to reach for some kind of tech, a product, a “solution”, I try to limit that reflex. Instead find that internal space, taking that breath, accepting a real world, appreciating it (ommm shanti, Jake). You want that good vision to go see good things.
If you like the plus, you’re getting stimulus, use it. If it’s experimenting, you like to try something new, it’s cool and curious, by all means. Use it. Above is just a bit of additional perspective.
As always, don’t go monkeying with lenses, unless you really know what you’re doing.  An open minded (and actual science minded) optometrist is always a potentially handy guide in this process. 
Semi-related, some thoughts on "plus lens therapy": {{#ev:youtube|X4k30dbjSc0|300|inline}}
''For those who get all huffy when I poke at plus lens therapy:  It’s  all not to say that plus lenses are bad.  It’s just potentially misleading to refer to a focal plane stimulus based approach by a specific lens type.  Great way to confuse people, and it’s also far too lens-centric of a thought process to make me feel comfortable.  What helps your eyesight is strain reduction and positive stimulus.  The kind of lens you may or may not need for this, secondary (and different for one person to the next).''}}
==Diopters==
==Diopters==
=====What should I reduce to?=====
=====What should I reduce to?=====
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If you have below 2 diopters of myopia, you can definitely look at not wearing glasses any more.
If you have below 2 diopters of myopia, you can definitely look at not wearing glasses any more.


See more: https://endmyopia.org/low-myopia-when-can-you-stop-wearing-glasses/
Blog post: [https://endmyopia.org/low-myopia-when-can-you-stop-wearing-glasses/ Low Myopia: When Can I Stop Wearing Glasses?]
 
==Contact lenses==
==Contact lenses==
===Should I use glasses or contact lenses for close-up?===
===Should I use glasses or contact lenses for close-up?===
You can wear [[contact lenses]] with [[plus lenses]] to achieve the same effect as a pair of [[differentials]]. It's generally preferable to wear glasses in general, but people have managed to improve their eyesight with contact lenses.
You can wear [[contact lenses]] with [[plus lenses]] to achieve the same effect as a pair of [[differentials]]. It's generally preferable to wear glasses in general, but people have managed to improve their eyesight with contact lenses.
{{jake says|(In particular for high myopes, these considerations.)
The tradeoff with glasses over contact lenses (for close-up use) is:
1) Cost (you’re going through a lot of lenses coming down from high myopia, and some people prefer higher index which is also more expensive).
2) Field of vision and image quality. Less of an issue for close-up, but you are going to get less visual quality from a high diopter lens than a high diopter contact lens (in most cases, though you can get somewhat closer with some very high quality, high index lenses).
3) Convenience. You can easily get some replacement contact lenses, experiment with them for reduced diopters. You can easily put a plus lens over contacts for immediate close-up and not carrying two pairs of glasses.
All in all though, I often suggest going with glasses. High diopter contact lenses are thicker, less gas permeable, and tend to cause more corneal abrasion. They disrupt tear fluid. While it always depends on the individual, it’s important to be aware of and consider all of these factors. }}
==How do I calculate math related to optics?==
==How do I calculate math related to optics?==
See [[optics related math]] for more information.
See [[optics related math]] for more information.
==Can you get better than 20/20 vision?==
{{jake says|If you’re already down to low myopia (1 diopter or less), then it might be time to start thinking about the benefits of going beyond 20/20 – into the single digits of 20/x.
Better night vision, incredible distance vision, reduced risk of recurring myopia, all things you probably want. [https://endmyopia.org/20x-2020-is-just-the-beginning/ Read this post for more.]}}
==Is it OK to use several different diopter glasses?==
Blog post: [https://endmyopia.org/qa-too-many-focal-plane-changes-whats-this-double-vision/ Q&A: Too Many Focal Plane Changes + What’s This Double Vision?]
==How do I reduce prescription complexity?==
{{jake says|Your prescription currently likely includes spherical, cylinder, and axis correction.  These numbers aren’t probably even all the same, for both eyes.  That’s prescription complexity, and it’s often not good for you, and likely not even necessary!
For the whole detailed explanation of how to reduce prescription complexity, visit this post:  https://endmyopia.org/pro-topic-how-to-reduce-prescription-complexity/}}
==See also==
==See also==
From the blog: [https://endmyopia.org/everything-in-one-place-the-big-primer-on-lenses-and-cost/ The Big Primer On Buying Lenses (And Cost!)]
From the blog: [https://endmyopia.org/everything-in-one-place-the-big-primer-on-lenses-and-cost/ The Big Primer On Buying Lenses (And Cost!)]

Latest revision as of 19:21, 19 February 2023

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Frequently Frequently
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(please read this!)
General
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About Myopia LASIK
Glasses &
diopters
Mindset Troubleshooting
The Process — EndMyopia Glossary
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Active Focus Habits Measurement Normalized Differentials Astigmatism Other
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Skepticism
About EM Paid course Other eyesight
conditions
Ineffective
Myopia Treatments

Buying glasses

Where should I buy glasses online?

See Category:Lens seller.

Blog post: Where Is The Best Place To Buy Glasses Online?

How do I measure pupillary distance?

Zenni Optical has a great article on this. Find that here

Are polycarbonate lenses bad for your eyes?

The fact that they are polycarbonate makes no difference to your eyes.

Blog post: Polycarbonate Lenses – Bad For Your Eyes?

How do I read my prescription?

See the Wiki guide to reading glasses prescriptions

How do I measure my PD? (pupillary distance)

Blog post: Headaches & Fatigue: Measure Your Pupillary Distance (PD)

Why are my glasses giving me a headache?

When myopia increases, people's headaches tend to get worse. This is largely due to the shrinking field of view higher diopter correction gives. There's a huge amount of variation in general in this area. It's safe to say though, the higher your diopters, the worse the headaches.

Page Template:Divbox/styles.css has no content.

My glasses are too thick and heavy, what do do?

You probably have high or severe myopia. See the severe myopia page for guidance on selecting lighter-weight glasses.

Test lens kits

Do I need a test lens kit?

No, generally you don't need a test lens kit. It may be helpful if your myopia is particularly complicated. Most people don't buy a test lens kit and do fine.

How do you use a test lens kit?

Trial test lens kit.jpg

You insert the lenses from the kit into the really dorky-looking glasses. This way you can test different lenses and how they work.

You can find optometrist approved guides on how to use a test lens kit here.

Where can I buy an optometrist test lens kit?

Page Template:Divbox/styles.css has no content.

Plus lenses

How do plus lenses work?

Plus lenses make you more short-sighted, not less. They are for the most part useless when it comes to improving myopia.

Should I use plus lenses to improve eyesight?

Page Template:Divbox/styles.css has no content.

Diopters

What should I reduce to?

See Guide:Reducing your correction.

Is it ok to use several different diopter glasses?

Generally, you want one pair of normalized, and one pair of differentials. You can wear more correction when doing important things such as driving at night - very important to do this safely.

Should I stop wearing glasses?

No, unless you have low myopia. See Explainer:Should I stop wearing glasses?

I have low myopia. Can I stop wearing my glasses?

If you have below 2 diopters of myopia, you can definitely look at not wearing glasses any more.

Blog post: Low Myopia: When Can I Stop Wearing Glasses?

Contact lenses

Should I use glasses or contact lenses for close-up?

You can wear contact lenses with plus lenses to achieve the same effect as a pair of differentials. It's generally preferable to wear glasses in general, but people have managed to improve their eyesight with contact lenses.

Page Template:Divbox/styles.css has no content.

How do I calculate math related to optics?

See optics related math for more information.

Can you get better than 20/20 vision?

Page Template:Divbox/styles.css has no content.

Is it OK to use several different diopter glasses?

Blog post: Q&A: Too Many Focal Plane Changes + What’s This Double Vision?

How do I reduce prescription complexity?

Page Template:Divbox/styles.css has no content.

See also

From the blog: The Big Primer On Buying Lenses (And Cost!)