Third Eyelid Gland Prolapse

What are the third eyelid and third eyelid gland?

Dogs have three eyelids, the third eyelid being an extra eyelid that sweeps back and forth across the surface of the eye providing protection and spreading the tear film. The third eyelid is also called the nictitating membrane. The tear film is produced by two glands, namely the third eyelid gland and the lacrimal gland. The third eyelid gland is attached to the base of the third eyelid where it is not normally visible.

What does ‘third eyelid gland prolapse’ mean?

The gland is held in its normal position at the base of the third eyelid by a small ligament which attaches it directly onto the bone of the eye socket. If the ligament breaks the gland becomes mobile, prolapsing or moving from its normal position and becoming visible above the edge of the third eyelid.

Why is it called ‘cherry eye’?

The prolapsed third eyelid gland is visible as a pink mass or lump near the inner corner of the eye and resembles a cherry.

How does the prolapsed gland affect the eye?

The gland does not produce tears effectively when it is in the wrong position, causing the surface of the eye to become dry. Although the condition is not usually painful it may cause minor irritation, conjunctivitis and increased discharge from the affected eye.

Is my dog or cat at risk?

Third eyelid gland prolapse is much more common in dogs than in cats. It usually affects young dogs between the ages of 6 to 12 months.

What are the treatment options?

The recommended treatment is surgery to replace the gland to its normal position at the base of the third eyelid where it cannot be seen and can function normally.  Removal of the gland is not a suitable option as it predisposes the eye to low tear production, or dry eye, later in life. Some breeds such as the Bulldog are predisposed to both ‘cherry eye’ and ‘dry eye’ conditions and it is therefore particularly important in such breeds that the prolapsed gland is replaced and not removed. If the gland is left untreated it will not produce tears normally and may become enlarged and red, causing discomfort.