Corneal injuries (erosions and ulcers) generally heal slowly. In order to protect the delicate cornea and provide lubrication during the healing process, the nictitans membrane (third eyelid) is pulled over the eye and temporarily sutured to the upper eyelid or the upper conjunctiva. When treating a recurrent superficial corneal erosion, a nictitans flap is commonly used following debridement of the injured corneal tissue.

The postoperative appearance of the eye is sometimes startling. Instead of seeing a normal eye, a pink membrane (which is actually the third eyelid) is seen in it's place. This membrane is pulled across the entire anterior portion of the eye.

Surgery with general anesthesia is required to produce a third eyelid flap.

The nictitans flap is a temporary procedure and is generally removed within two weeks. If there is any problem with this membrane, or if it has an unusual appearance, the Veterinarian should be notified.