Cataract is a medical condition in which the lens of the eye becomes progressively opaque, resulting in blurred vision.
The crystalline lens of the eye is enclosed behind the pupil (the coloured part), inside a transparent lining called "the lens capsule”.
It is not important how serious the clouding of the eye is, nor if it affects all the lens or just a part of it.
Cataract treatment is always the same and it is advisable to remove the opaque lens and replace it with an artificial one.