Cherry eye

Cherry eye is a common term for a prolapse (bulging out) of the third eyelid gland. The third eyelid has a small gland on its inner surface that produces about 30% of the tear film. In some breeds the ligament responsible for holding the gland anchored weakens, thereby allowing the gland to prolapse. This appears as a smooth fleshy swelling from the inside corner of the lower eyelid.

Cherry eye in cats is rare, but can occur in Burmese and Persians. The condition is usually seen in young dogs (6 months to 2 years)
Once prolapsed the gland begins to swell and become hyperaemic (reddened) due to drying from environmental exposure.
Simply replacing the gland is unsuccessful as it will likely prolapse again within the next 24 hrs. Surgical removal of the gland has been the treatment however it has been found that there is an increased possibility of developing a dry eye (keratoconjunctivitis sicca), as a result of the lost tear production from this gland. A number of surgical techniques that anchor the gland inside the lining of the lid have been developed and are considered preferable treatments. These techniques do however have a recurrence rate of between 5-20%.