Difference between revisions of Lens
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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]]. | ||
== | ==Worn Correction== | ||
If the [[refractive state]] of your eye causes [[myopia]] or [[hyperopia]] then you probably wear contacts or glasses. | 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 | 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 ==== |