What is a cataract?

In our eye we have a lens, and when we are young, the lens is clear, like clear glass. But as we get older, the lens can get cloudy. This cloudiness affects the light passing through the eye to the retina and that can cause vision to not be as clear as before . Most people aged 65 and older have a cataract. Rarely, children can be born with a cataract and this is termed congenital cataract.

The lens is made mostly of water and protein. The protein is arranged in a particular structure to let light pass through and focus on the retina. As we age, sometimes some of the protein clumps together. This can start to cloud small areas of the lens, blocking some light from reaching the retina and interfering with vision. This is a cataract. Most people believe a cataract is a film that grows across the eye, but this is not the case. It is actually part of the clear lens becoming cloudy. Because this is a natural part of ageing, no drops can prevent or slow down cataract development. A cataract won’t spread from one eye to the other, although many people develop cataracts in both eyes.

In its early stages, a cataract may not cause a problem. The cloudiness may affect only a small part of the lens. However, over time, the cataract may grow larger and cloud more of the lens, making it harder to see. Because less light reaches the retina, your vision may become dull and blurry. Night vision may become worse. Some patients find colours get duller and not as distinct as before.

In the early stages, stronger lighting and eyeglasses may lessen vision problems caused by cataracts. At a certain point, however, surgery will be needed to improve vision. Today, cataract surgery is safe and very successful. During a cataract operation, the ophthalmologist removes the cloudy lens, and replaces it with an artificial one, called an intraocular lens implant (IOL).

Although researchers are learning more about cataracts, no one knows for sure what causes them to occur early in some people. Scientists think there may be several causes, including smoking, diabetes, and excessive exposure to sunlight.