Cataracts occur when the natural lens of the eye becomes cloudy. This causes foggy and/or blurred vision. Cataracts are a very common condition, nearly everyone over 60 years old has some formation of cataracts.

Other factors that can cause cataracts are eye injuries, diabetes, a family history of cataracts, poor diet and smoking as well as some types of medication.
At first a cataract has little effect on your vision. They often develop slowly and can affect one or both eyes. Mild cataracts can be managed with glasses but once the lens becomes too cloudy, surgery becomes the only practical treatment.

Normal vision

Light entering the eye is normally focused perfectly on the retina when the lens is clear.

Vision with a cataract

When a cataract has developed, the clouded lens scatters light, causing vision to deteriorate.


Your vision may be hazy or a little blurred and can be compared to looking through a foggy window or a dirty camera lens. A cataract may make it difficult for you to read or see clearly into the distance. It can also create glare, making driving at night particularly difficult with the glare from street lights and/or car headlights.

Other symptoms can include a change in the appearance of colours – most typical is colours appearing faded or yellowing. The focussing power of the eye can also be affected by cataracts. Frequent spectacle prescription changes may indicate a cataract is developing.