Cataracts are not a film on the cornea. Rather they affect one of the eye's structure called the crystallin. The crystallin is the lens of the eye, much like the lens of a camera. Usually the crystallin is transparent and enables the eye to clearly focus on objects both near and far. However, it can become cloudy and cause images to appear blurred. Over time, it can also become opaque and completely block vision in the affected eye. That's what we call a cataract. Cataracts are the third cause of blindness in North America. They are not contagious from eye to eye. However, people who have a cataract in one eye usually end up having cataracts in both eyes.
The main cause of cataracts is aging. By 75 years of age, about one out of every two persons will be affected. Other causes include eye injury or congenital defect. Other factors can also increase the risk when combined with aging, such as chronic diseases (mainly diabetes), genetics, sun exposure, smoking and use of certain drugs like steroids.
Cataracts usually appear around age 50 and cause a gradual loss of vision. They are not painful and are not associated with tingling or burning sensations. Here are some signs of cataracts:
- blurred or clouded vision
- dazzled vision
- poor night vision
- seeing a halo around lights
- better vision in one eye
- impression of looking through a frosted glass
- color seems faded
If you have some of these symptoms, see your eye care professional for a complete eye exam to determine if you do have cataracts.
A surgery can be performed to replace the cloudy lens by an artificial plastic lens (implant). As a result, vision will be greatly improved and should remain stable. Surgery is recommended when performing daily tasks becomes difficult because of poor vision. Typically, one eye is operated on at a time and surgery is done under local anaesthesia (anaesthetic drops). New bifocal implants are now available. These correct both near- and farsightedness making it possible for people not to wear glasses.
For more information :
The Information Service of the Canadian Ophtalmological Society
Canadian National Institute for the Blind (CNIB)