In about a third of cataract surgery cases, the clear capsule that holds the new plastic, silicone or acrylic lens becomes cloudy or frosted over. This can occur weeks, months, or years after the original cataract surgery; usually it's years. Again, vision is reduced. Some people think their cataract has returned, but it can be easily treated with the YAG laser.

During the short procedure, the beam of laser light is used to make a small opening in the back of the cloudy capsule to restore clear vision. Once the capsule is opened it usually never clouds over again.