Library · Anatomy
Lens
Make it clearer
The crystalline lens is the eye's natural lens. It is a transparent structure made of fibers, which are really modified epithelial cells, and all of that content is wrapped in a membrane called the lens capsule.
Its job is focusing. The cornea, the clear layer at the front of the eye, and the lens together supply the optical power that focuses light into an image on the retina, the layer at the back that captures light. And the lens can adjust that focus: when the ciliary muscle around it contracts, the lens thickens, shortens its focal length and gains refractive power, that is, more ability to bend light. It is a gelatin lens that changes shape to focus up close.
That same material explains its best-known disease. When various degenerative processes denature and coagulate the proteins in those fibers, the lens loses its transparency and a cataract forms: a clouding of the lens, or of its capsule, that gets in the way of light reaching the retina.
In brief
The lens is a transparent structure made of fibers, which are modified epithelial cells, wrapped in a membrane called the lens capsule.
With the cornea it supplies the optical power that focuses light on the retina; when the ciliary muscle contracts, the lens thickens, shortens its focal length and gains refractive power.
A gelatin lens that changes shape to focus up close.
When degenerative processes denature the proteins in those fibers, the lens loses its transparency and a cataract forms.
Sources (2)
- National Center for Biotechnology Information, StatPearls PublishingCataract, StatPearlsPublished
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Accommodation, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated