Cataract is a condition in which the natural clear lens of the eye becomes cloudy and reduces the amount of light entering the eye. This results in a gradual progressive deterioration of vision. It is the commonest cause of blindness in the world.

Cataract is most commonly caused by a natural aging process. It often occurs in the elderly and is believed to be related to UV light exposure. Certain medical conditions, such as diabetes mellitus, long term use of certain medication, severe injury or chronic inflammation can also increase the risk of developing cataracts. Occasionally, it may also occur in the young.