Cataracts are a clouding of the eye’s crystalline lens that usually develops slowly over time. (In the case of post-traumatic cataracts, however, they can also occur very quickly.) It is the leading cause of poor vision in adults.

Symptoms: Dimmed or blurred vision, double vision, halos or glare around lights, dull colors, sensation of a film over the eyes, frequent cleaning of the eyes, difficulty driving or reading, and frequent changing or cleaning of glasses.

Treatment: If a cataract grows larger or denser, it can be surgically removed. It is a safe procedure with a near 100 per cent success rate. Following surgery, it is normal to require a change in spectacle correction.

Prevention: Wearing UV protection when outdoors is very helpful. There is also some evidence to suggest that a diet high in beta carotene (vitamin A), selenium and vitamins C and E have preventative benefits. Avoiding cigarette smoke, air pollution and alcohol consumption may also help.