Lens - Revision history

User: /* Distortion Effects */

2021-09-18T20:51:59Z

Distortion Effects

← Older revision		Revision as of 20:51, 18 September 2021
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	==== Distortion Effects ====		==== Distortion Effects ====
	Glasses are only perfectly tuned through their optical centers. If your [[Pupillary Distance]], Pupillary height, or lens adjustment are off, you might not be looking through the optical center of the lens, and you are certainly not looking through the optical center when you look around instead of straight ahead. The power of the lens will vary, and unintentional prism ~~or cylinder~~ can be introduced. You may also not be wearing the lens at the intended vertex distance, affecting the effective power of the lens. The stronger the lens the more of a difference this makes.		Glasses are only perfectly tuned through their optical centers. If your [[Pupillary Distance]], Pupillary height, or lens adjustment are off, you might not be looking through the optical center of the lens, and you are certainly not looking through the optical center when you look around instead of straight ahead. The power of the lens will vary, and unintentional prism can be introduced by decentration. You may also not be wearing the lens at the intended vertex distance, affecting the effective power of the lens. The stronger the lens, the more of a difference this makes.

	=== Contacts ===		=== Contacts ===

User: /* Distortion Effects */

2021-09-18T20:51:31Z

Distortion Effects

← Older revision		Revision as of 20:51, 18 September 2021
Line 11:		Line 11:

	==== Distortion Effects ====		==== Distortion Effects ====
	Glasses are only perfectly tuned through their optical centers. If your [[Pupillary Distance]], Pupillary height, or lens adjustment are off, you might not be looking through the optical center of the lens, and you are certainly not looking through the optical center when you look around instead of straight ahead. The power of the lens will vary, and unintentional cylinder can be introduced. You may also not be wearing the lens at the intended vertex distance, affecting the effective power of the lens. The stronger the lens the more of a difference this makes.		Glasses are only perfectly tuned through their optical centers. If your [[Pupillary Distance]], Pupillary height, or lens adjustment are off, you might not be looking through the optical center of the lens, and you are certainly not looking through the optical center when you look around instead of straight ahead. The power of the lens will vary, and unintentional prism or cylinder can be introduced. You may also not be wearing the lens at the intended vertex distance, affecting the effective power of the lens. The stronger the lens the more of a difference this makes.

	=== Contacts ===		=== Contacts ===

User: /* See Also */

2021-08-29T00:30:31Z

Dlskidmore: /* Contacts */ Cautions about 3rd party sources

2020-09-17T18:42:03Z

Contacts: Cautions about 3rd party sources

← Older revision		Revision as of 18:42, 17 September 2020
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	* Since it's easiest to get contacts at full prescription, and many people want contacts for outdoor activity, most people use prescription contacts and [[plus lenses]] over. This may put you in the range to use cheap drug store readers, but it's better to get good ones from a custom [[lens seller]].		* Since it's easiest to get contacts at full prescription, and many people want contacts for outdoor activity, most people use prescription contacts and [[plus lenses]] over. This may put you in the range to use cheap drug store readers, but it's better to get good ones from a custom [[lens seller]].
	* The next most common strategy is to use differential contacts with [[minus lenses]] over for [[normalized]]. This has the advantage of less total lens over the eye, and a thinner contact may be more comfortable and allow more oxygen through to the surface of the eye. (And in specific cases may affect the cost of contact lenses, when stepping down from the extended range brand to the normal range brand in the same material/design.) This has the disadvantage of requiring glasses for outdoor activity.		* The next most common strategy is to use differential contacts with [[minus lenses]] over for [[normalized]]. This has the advantage of less total lens over the eye, and a thinner contact may be more comfortable and allow more oxygen through to the surface of the eye. (And in specific cases may affect the cost of contact lenses, when stepping down from the extended range brand to the normal range brand in the same material/design.) This has the disadvantage of requiring glasses for outdoor activity.

			====Cautions about 3rd party sources====
			If you buy glasses online, you can pretty much get optically clear glass and an anti reflective coating in any of the cheap brands. When wearing contacts, oxygen permeability and the fit of the lens to your eye surface are important to eyeball health. Whenever possible, get contacts fitted by a professional [[optometrist]]. If you get any contacts other than those you are fitted for, you introduce significant additional risks on top of the expected contacts risks. You can get contacts in the same brand, material, diameter, and base curve as your professionally fitted ones, but event the difference in thickness could affect fit. A bad fit may not be obvious to the wearer, but can cause damage to the cornea over time.<ref>https://coopervision.com/sites/coopervision.com/files/pfg0001_revg_biofinity_family_pfg_clean_sep2019.pdf</ref>

	==See Also==		==See Also==

Dlskidmore: /* Contacts */ Expanded Howto

2020-09-06T03:26:36Z

Contacts: Expanded Howto

← Older revision		Revision as of 03:26, 6 September 2020
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	=== Contacts ===		=== Contacts ===
	Contact lenses are in physical contact with your eye, and have a vertex distance of 0. They carry high risks of infection, [[dry eye]] and other eye injuries, and require extensive care, and are hard to swap out multiple times a day, but have fewer distortion effects than glasses at higher powers. ~~Typically when~~ contacts ~~are used in the EM method~~, ~~they are supplemented with tuning glasses over to get the multiple focal planes needed. For example~~, ~~you might wear contacts that are selected to be [[differentials]] and wear [[minus lenses]] over for~~ [[normalized]] or ~~you might wear full prescription contacts, with two powers of~~ [[~~plus lenses~~]] over to ~~reach normalized and differential powers~~. This ruins the cosmetic benefits of wearing contacts, but may make the process easier for people with strong lenses or who need to not wear glasses for sports or other reasons.		Contact lenses are in physical contact with your eye, and have a vertex distance of 0. They carry high risks of infection, [[dry eye]] and other eye injuries, and require extensive care, and are hard to swap out multiple times a day, but have fewer distortion effects than glasses at higher powers.
			====How to use Contacts with EM====
			Choose a power for your contacts to match, your prescription, [[normalized]], or [[differentials]], and then use glasses over the contacts to get to the other focal planes you need. This ruins the cosmetic benefits of wearing contacts, but may make the process easier for people with strong lenses or who need to not wear glasses for sports or other reasons.

			* Since it's easiest to get contacts at full prescription, and many people want contacts for outdoor activity, most people use prescription contacts and [[plus lenses]] over. This may put you in the range to use cheap drug store readers, but it's better to get good ones from a custom [[lens seller]].
			* The next most common strategy is to use differential contacts with [[minus lenses]] over for [[normalized]]. This has the advantage of less total lens over the eye, and a thinner contact may be more comfortable and allow more oxygen through to the surface of the eye. (And in specific cases may affect the cost of contact lenses, when stepping down from the extended range brand to the normal range brand in the same material/design.) This has the disadvantage of requiring glasses for outdoor activity.

	==See Also==		==See Also==

Viceroy Sam: /* Contacts */typos fixed: For example → For example,

2020-06-11T15:34:13Z

Contacts: typos fixed: For example → For example,

← Older revision		Revision as of 15:34, 11 June 2020
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	=== Contacts ===		=== Contacts ===
	Contact lenses are in physical contact with your eye, and have a vertex distance of 0. They carry high risks of infection, [[dry eye]] and other eye injuries, and require extensive care, and are hard to swap out multiple times a day, but have fewer distortion effects than glasses at higher powers. Typically when contacts are used in the EM method, they are supplemented with tuning glasses over to get the multiple focal planes needed. For example you might wear contacts that are selected to be [[differentials]] and wear [[minus lenses]] over for [[normalized]] or you might wear full prescription contacts, with two powers of [[plus lenses]] over to reach normalized and differential powers. This ruins the cosmetic benefits of wearing contacts, but may make the process easier for people with strong lenses or who need to not wear glasses for sports or other reasons.		Contact lenses are in physical contact with your eye, and have a vertex distance of 0. They carry high risks of infection, [[dry eye]] and other eye injuries, and require extensive care, and are hard to swap out multiple times a day, but have fewer distortion effects than glasses at higher powers. Typically when contacts are used in the EM method, they are supplemented with tuning glasses over to get the multiple focal planes needed. For example, you might wear contacts that are selected to be [[differentials]] and wear [[minus lenses]] over for [[normalized]] or you might wear full prescription contacts, with two powers of [[plus lenses]] over to reach normalized and differential powers. This ruins the cosmetic benefits of wearing contacts, but may make the process easier for people with strong lenses or who need to not wear glasses for sports or other reasons.

	==See Also==		==See Also==

Dlskidmore: minor clarification, EM proposes that long term adjustments are possible elsewhere.

2020-06-10T16:23:27Z

minor clarification, EM proposes that long term adjustments are possible elsewhere.

← Older revision		Revision as of 16:23, 10 June 2020
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	==Crystalline Lens==		==Crystalline Lens==
	This is the lens inside your [[eyeballs]]. It is not actually the strongest part of your internal [[refractive state]] but it is the part that is adjustable. The [[ciliary muscle]] can flex this lens and change it's power. The ability to change the power of this lens to focus on near work is called [[accommodation]]. As you age, the crystalline lens thickens and is prone to [[presbyopia]] and [[cataracts]].		This is the lens inside your [[eyeballs]]. It is not actually the strongest part of your internal [[refractive state]] but it is the part that is quickly adjustable. The [[ciliary muscle]] can flex this lens and change it's power. The ability to change the power of this lens to focus on near work is called [[accommodation]]. As you age, the crystalline lens thickens and is prone to [[presbyopia]] and [[cataracts]].

	==Worn Correction==		==Worn Correction==

Dlskidmore: Moving some stuff that didn't really belong where it was. + spelling

2020-06-10T16:21:24Z

Moving some stuff that didn't really belong where it was. + spelling

← Older revision		Revision as of 16:21, 10 June 2020
Line 1:		Line 1:
	A lens is any medium that transmits light and has an [[Index of Refraction]] and shape designed to bend light. Lenses come in many forms but there's a few critical ones that relate to EM.		A lens is any medium that transmits light and has an [[Index of Refraction]] and shape designed to bend light. The strength of lenses are measured in [[diopters]]. Lenses come in many forms but there's a few critical ones that relate to EM.

	==Crystalline Lens==		==Crystalline Lens==
	This is the lens inside your [[eyeballs]]. It is not actually the strongest part of your internal [[refractive state]] but it is the part that is adjustable. The [[ciliary muscle]] can flex this lens and change it's power. The ability to change the power of this lens to focus on near work is called [[accommodation]]. As you age, the crystalline lens thickens and is prone to [[presbyopia]] and [[cataracts]].		This is the lens inside your [[eyeballs]]. It is not actually the strongest part of your internal [[refractive state]] but it is the part that is adjustable. The [[ciliary muscle]] can flex this lens and change it's power. The ability to change the power of this lens to focus on near work is called [[accommodation]]. As you age, the crystalline lens thickens and is prone to [[presbyopia]] and [[cataracts]].

	==~~Glasses or Contacts~~==		==Worn Correction==
	If the [[refractive state]] of your eye causes [[myopia]] or [[hyperopia]] then you probably wear contacts or glasses. ~~The EM method addresses~~ the ~~[[spherical]] and [[cylinder]] components of~~ your ~~[[prescription]]. The strength of~~ your ~~lenses are measured in [[diopters]]~~.		If the [[refractive state]] of your eye causes [[myopia]] or [[hyperopia]] then you probably wear contacts or glasses. This "corrects" the light coming into your eye to compensate for the refractive state in your eye.

	=== Glasses ===		=== Glasses ===
	Glasses are lenses worn in front of the face, typically at a [[vertex distance]] of 10 to 13 cm. Glasses are easily changed and have lower risks than contact lenses, but at higher powers may have some ~~tradeoffs~~.		Glasses are lenses worn in front of the face, typically at a [[vertex distance]] of 10 to 13 cm. Glasses are easily changed and have lower risks than contact lenses, but at higher powers may have some trade-offs.

	==== Distortion Effects ====		==== Distortion Effects ====

Dlskidmore: How contacts are used in EM

2020-06-10T16:16:40Z

How contacts are used in EM

← Older revision		Revision as of 16:16, 10 June 2020
Line 14:		Line 14:

	=== Contacts ===		=== Contacts ===
	Contact lenses are in physical contact with your eye, and have a vertex distance of 0. They carry high risks of infection, [[dry eye]] and other eye injuries, and require extensive care, and are hard to swap out multiple times a day, but have fewer distortion effects than glasses at higher powers.		Contact lenses are in physical contact with your eye, and have a vertex distance of 0. They carry high risks of infection, [[dry eye]] and other eye injuries, and require extensive care, and are hard to swap out multiple times a day, but have fewer distortion effects than glasses at higher powers. Typically when contacts are used in the EM method, they are supplemented with tuning glasses over to get the multiple focal planes needed. For example you might wear contacts that are selected to be [[differentials]] and wear [[minus lenses]] over for [[normalized]] or you might wear full prescription contacts, with two powers of [[plus lenses]] over to reach normalized and differential powers. This ruins the cosmetic benefits of wearing contacts, but may make the process easier for people with strong lenses or who need to not wear glasses for sports or other reasons.

	==See Also==		==See Also==

Dlskidmore: glasses and contacts details.

2020-06-10T16:08:18Z

glasses and contacts details.

← Older revision		Revision as of 16:08, 10 June 2020
Line 1:		Line 1:
	A lens is any medium that transmits light and has an [[Index of Refraction]] and shape designed to bend light. Lenses come in many forms but there's a few critical ones that relate to EM.		A lens is any medium that transmits light and has an [[Index of Refraction]] and shape designed to bend light. Lenses come in many forms but there's a few critical ones that relate to EM.

	=Crystalline Lens=		==Crystalline Lens==
	This is the lens inside your [[eyeballs]]. It is not actually the strongest part of your internal [[refractive state]] but it is the part that is adjustable. The [[ciliary muscle]] can flex this lens and change it's power. The ability to change the power of this lens to focus on near work is called [[accommodation]]. As you age, the crystalline lens thickens and is prone to [[presbyopia]] and [[cataracts]].		This is the lens inside your [[eyeballs]]. It is not actually the strongest part of your internal [[refractive state]] but it is the part that is adjustable. The [[ciliary muscle]] can flex this lens and change it's power. The ability to change the power of this lens to focus on near work is called [[accommodation]]. As you age, the crystalline lens thickens and is prone to [[presbyopia]] and [[cataracts]].

	=Glasses or Contacts=		==Glasses or Contacts==
	If the [[refractive state]] of your eye causes [[myopia]] or [[hyperopia]] then you probably wear contacts or glasses. The EM method addresses the [[spherical]] and [[cylinder]] components of your [[prescription]]. The strength of your lenses are measured in [[diopters]].		If the [[refractive state]] of your eye causes [[myopia]] or [[hyperopia]] then you probably wear contacts or glasses. The EM method addresses the [[spherical]] and [[cylinder]] components of your [[prescription]]. The strength of your lenses are measured in [[diopters]].

	=See Also=		=== Glasses ===
			Glasses are lenses worn in front of the face, typically at a [[vertex distance]] of 10 to 13 cm. Glasses are easily changed and have lower risks than contact lenses, but at higher powers may have some tradeoffs.

			==== Distortion Effects ====
			Glasses are only perfectly tuned through their optical centers. If your [[Pupillary Distance]], Pupillary height, or lens adjustment are off, you might not be looking through the optical center of the lens, and you are certainly not looking through the optical center when you look around instead of straight ahead. The power of the lens will vary, and unintentional cylinder can be introduced. You may also not be wearing the lens at the intended vertex distance, affecting the effective power of the lens. The stronger the lens the more of a difference this makes.

			=== Contacts ===
			Contact lenses are in physical contact with your eye, and have a vertex distance of 0. They carry high risks of infection, [[dry eye]] and other eye injuries, and require extensive care, and are hard to swap out multiple times a day, but have fewer distortion effects than glasses at higher powers.

			==See Also==
	* [[lens selections]]		* [[lens selections]]

	[[Category:Articles]]		[[Category:Articles]]

← Older revision		Revision as of 00:30, 29 August 2021
Line 25:		Line 25:

	==See Also==		==See Also==
	* [[~~lens~~ selections]]		* [[Diopters#Technical Details]]
			* [[Lens selections]]

	[[Category:Articles]]		[[Category:Articles]]