The cornea is the front clear window of the eyeball. It is a unique part of the body which is organised in a way to keep it transparent and crystal clear. You can see the coloured iris and the pupil which is the black in the centre of the iris through the cornea.
The cornea has many functions, one of it is to helps to focus light rays on to the retina (the light-sensitive film at the back of the eye). This “picture” is then transmitted to the brain.
When the cornea is damaged, it can become less transparent or its shape can change. This can prevent light reaching the retina and causes the picture transmitted to the brain to be distorted or unclear.