From several months to several years after successful cataract surgery, a cloud may develop behind the lens implant.

This is called a secondary cataract and will blur vision much as the original cataract did.

The YAG laser is used in the treatment of secondary cataracts. The YAG laser makes a small opening in the cloudy membrane behind the lens implant. This requires 2 minutes and usually results in immediate vision improvement. The YAG laser is not used for the original cataract surgery.