A Yag capsulotomy is a special laser treatment used to improve your vision after cataract surgery. It is a simple, commonly performed procedure which is very safe. During your cataract operation, the natural lens inside your eye that had become cloudy was removed. A new plastic lens was put inside the lens membrane (called the bag or capsule) in your eye. In a small number of patients, the capsule thickens after surgery and becomes cloudy. This interferes with the light reaching the back of the eye. When this happens, your sight becomes misty, and you may get glare in bright light or from lights at night-time. Capsule thickening can happen in the months after your cataract operation, but more commonly occurs about two years after surgery. Yag laser capsulotomy is the only way to treat this. Apart from affecting your vision, the thickening does not damage the eye in any way. In a Yag laser capsulotomy the doctor uses a special lens to apply a laser beam to the capsule. This creates a small hole in the centre of the capsule, which lets light through.