The eyes are enormously complex and delicate, but basically they function like an analog camera. Clear vision depends on light being able to enter the eyes and travel unobstructed through to the back inside surface – the retina, which is like the camera film.
The incoming light passes first through the cornea, the clear front eye covering. Then it passes through the pupil, that black opening in the iris, the colored part. Next it passes through the lens, then the clear fluid which fills most of the eyeball. Behind this fluid is the retina. Both the cornea and lens bend the light to focus it on the retina, and that gives you clear vision.
Cataracts interrupt the flow of light and prevent some of it from reaching the retina. They are tiny clumps of protein in the lens. The lens consists mostly of water and proteins but as we age and the body becomes drier, the protein begins to stick together. At first cataracts are tiny but they grow and increase in number. Left untreated they will eventually cause blindness.
There are three ways that cataracts can form and spread in the lens:
From the center outwards
From the periphery inwards
On the back surface of the lens
You can read more on our Cataracts page. Cataracts cannot be removed from the lens, so surgery must be done to remove the lens from the eye and replace it with an intraocular lens (IOL).
If you are concerned that you may be developing cataracts, or if you would like to learn more about them and how they affect your vision, please contact an experienced cataract ophthalmologist in your area.