In a normal eye, the lens—which lies behind the pupil—is clear (transparent), so the pupil appears black. In an eye with a severe cataract, the cataract clouds the lens, so that the pupil appears gray or cloudy.

The cornea is the clear layer that covers the front of the eye. The lens is contained inside the eye's lens capsule. A cataract is a partial or complete cloudiness in the lens.

A cut (incision) about 3 mm wide is made in the eye where the clear front covering of the eye (cornea) meets the white of the eye (sclera). Next, a small, circular opening is created in the front lining of the lense (anterior capsule) to allow access to the cataract. A small surgical instrument (Phaco probe) is inserted through the incision and through the open anterior capsule.

Sound waves (ultrasound) are used to break the cataract into small pieces. Then the surgeon removes the cataract and lens pieces from the eye using suction.

A variety of IOL types are available to replace your natural lens. Your doctor can help you choose the type that may work best for you.

After the cataract is removed, an intraocular lens (IOL) may be placed in front of the back lining of the lens (posterior lens capsule). The back of the lens capsule is left inside the eye to keep the clear gel in the back of the eye (vitreous gel), as well as the IOL, in place.

The intraocular lens (IOL) takes the place of the eye's natural lens. The incision does not usually require stitches, unless the surgeon decides they are needed.

Before cataract surgery, the cloudy lens can be seen through the pupil. After cataract surgery, the pupil appears black because the intraocular lens is clear.