Cherry Eye: Prolapse of the Nictitans Gland

Cherry eye is the popular, and very apt, name given to a condition that can affect the third eyelids of many breeds of young dogs. 

The third eyelid or nictitating membrane is a fold of conjunctiva supported by a T-shaped cartilage. It normally rests at the inner corner (medial canthus) of the eye and moves across the cornea, (the clear part of the eye) when the upper and lower eyelids are closed.  It acts as an extra means of protection to the eye and moves a bit like a windscreen wiper.

On the inner surface (that facing the eyeball) of the third eyelid there is an important gland involved with tear production. It is the prolapse and enlargement (hypertrophy), of this gland which results in so-called cherry eye. The whole of the third eyelid appears swollen, often with the meaty looking gland appearing beyond the edge and partially covering the cornea (like a bright red cherry).

The cause of the problem is unknown.

Can it occur in any breed?

It can occur in any breed but it is seen more frequently in bulldogs, boxers and hounds such as Bassets together with American Cocker Spaniels, and Lhasa Apsos. It is also quite common in giant breeds such as Great Danes and Neapolitan Mastiffs.

What symptoms should I look for?

There may be no definite signs apart from the mass protruding from the inner corner of the eye. Sometimes a watery discharge accompanies the swelling.

Is it painful?

In the majority of dogs the condition does not appear to cause any discomfort. Young puppies occasionally find the mass irritating and can damage the protruding gland by pawing or rubbing the face on the ground.

"In the majority of dogs the condition does not appear to cause any discomfort."

Can anything else cause similar swelling?

Diagnosis is usually straightforward in young puppies. In older dogs further investigation may be necessary since it is possible that the mass may be due to a rapidly growing tumour.

Can the other eye be affected?

In the susceptible breeds it is not uncommon for the condition to occur first in one eye and then in the other. Occasionally it can occur in both eyes at the same time.

What does treatment involve?

The application of anti inflammatory preparations (drops or ointment) to the eye sometimes reduces the amount of swelling of the protruding gland but this is seldom permanent. In the majority of cases surgery has to be performed to return the protruding tissue to its normal location. This is quite delicate surgery and your dog may be referred to a veterinary ophthalmologist.

Are there any complications?

If the protruding tissue is very large it is occasionally necessary to remove part of it. This is only usually undertaken as a last resort since the gland does have an important function concerned with protection and lubrication of the eye via the tears it produces. If removal is inevitable there is always the possibility that dry eye, (Keratoconjunctivitis sicca – KCS) due to insufficient production of tears, may develop. This may require ongoing treatment.