The lens capsule is a thin membrane around the eye's natural lens. The capsule helps give the lens its shape.
When your natural lens becomes cloudy, your ophthalmologist removes it with cataract surgery. During surgery, an artificial intraocular lens or IOL is inserted into the lens capsule in place of your cloudy lens. Sometimes the capsule itself can become cloudy over time after surgery. This is called posterior capsule opacification or PCO. PCO can make it seem as if your cataract has returned. In fact, a cataract cannot return because your natural lens is gone. But a simple in-office laser procedure, called a posterior capsulotomy or YAG laser capsulotomy, can restore clear vision.