YAG capsulotomy is a laser eye treatment that is used to improve vision after cataract surgery. (Also called a secondary cataract) In some patients, typically less than 20 % of patients, total vision can become cloudy again after cataract surgery. This happens because the posterior capsule, which holds the lens in place, becomes cloudy and impairs vision. A laser is directed at the capsule and a small cut is made with the laser to open it and allow clear passage of light to the back of the eye. The procedure only takes a few minutes and is completely painless. Side effects of this procedure are rare and in very few cases, the eye becomes inflamed after the procedure and may require some treatment.