Cataract is the clouding of the eye’s natural lens. Cataract is one of the most common cause of vision loss in people above 50 years of age and one of the major cause for blindness in the world. By age 60, more than half of all Indian patients have either developed a cataract or have had cataract surgery. A cataract may occur in one or both eyes. It can not spread from one eye to the other.

The lens inside the eye is like a camera lens, focusing light onto the retina for clear vision. It adjusts the eye's focus allowing us to view things clearly, both close and far away. The human eye lens is mostly made of water and protein. This protein is arranged in a precise way to allow light to pass through it adequately. But as we age, some of the protein may clump together and this starts to cloud a small area of the lens. This is known as cataract. Over a period of time, it may grow larger and cloud the lens, making it harder to see.