Cataract is a condition that occurs when the natural lens inside the eye loses its transparency and becomes cloudy, and is characterized by a decrease or deterioration in the quality of vision.

Depending on the severity of the cataract, the patient may complain of smoky or blurry vision, and in advanced cases, vision may decrease significantly. Initially, the patient sees as if looking through a tulle curtain. Depending on the location and degree of cataract onset, some say they see less in bright light, while others see less in dim light.