Lens

The lens - The lens makes it possible for us to see sharp on different distances. The lens is covered by a lens capsule. The lens is fastening to the steel body with thin threads, so called zonular threads. When the steel body's muscle contracts, the threads will be lax and the lens rounder and its refraction power increase. It's calling accommodate. When the muscles are relaxed, the treads and the lens will be flatter.

The lens contains of thread that reproduces all the time, this means that the lens will be thicker and thicker. Already in age of 30 the earliest produced threads, which is situated in the middle of the lens, be more firm and less form able. This is due to the water content in the threads decreases. The more firm the lens will be, the less elastic it will be, which means that the eye cannot accommodate as much as before. Presbyopia will be the result and reading glasses is needed to see in a closer range. Sometimes the lens will be muddy and has to be changed by an operation.

Lens capsule - the lens capsule is a very elastic membrane which covers the lens. This gives a pressure to the lens, which gives the lens firmness. By the modern cataract operation the lens capsule is left and inside this a lens is placed. Sometimes the lens capsule is muddy after the operation, this is called the post cataract and it's treated by laser.