Secondary cataract – capsular clouding that occurs in about 40% to 50% or even more of cases after cataract surgery. Secondary cataract present as a gradual decline in visual acuity and blurred vision months or years after cataract surgery. Capsular opacification results from the migration and proliferation of epithelial cells to the posterior capsule. Proliferation impairs both distance and near vision. The patient may also perceive glare at the sun or car headlights at night and a decrease in color perception.

To restore lost vision, an opening or window is made in the center of the posterior capsule. The procedure is called a capsulotomy and is done using a YAG laser.