Cherry Eye and Kerato-Conjunctivitis Sicca

Cherry eye is the common name for a condition that is caused when the gland of the third eyelid of the dog (otherwise known as the Hardarian or Nictitans gland), becomes inflamed, swells up and pops out in front of the eye. It becomes inflamed, swollen and irritated and can cover 1/3 of the whole eyeball of the dog.  It can be expected that if the gland of one eye prolapses, that there is a high probability of the second eye also prolapsing within a few months.

Historically when dogs developed cherry eye, the gland would simply be removed. However, in the past decade, it has become the common and recommended practice to attempt to replace the gland by various methods. This is due to the problem of reduced tear production leading to a condition called “dry eye” or keratoconjunctivitis sicca (KCS).  KCS is a serious condition causing significant discomfort to the dog and requiring ongoing daily medication to the eye for ever. Tear flow is measured by means of the Schirmer Tear Test and should be between 14 and 24 mm in a minute. Breeds particularly susceptible to KCS include many of the brachycephalic breeds, and include the following:

Miniature Schnauzer

Cocker Spaniel

English Bulldog

Beagle

Poodle

Pug

Pekenese

Shih Tzu

Lhasa Apso

Yorkshire terrier

West Highland Terrier

Boston Terrier

Currently the most commonly recommended surgical procedure for the replacement of “cherry eye” is called "the pocket technique”. In a retrospective study the following results were found:

1. If the gland was left out and untreated, 43% of the eyes developed KCS
2. if the gland was excised 48% of the eyes developed KCS
3. but if the gland was surgically replaced only 14% of the eyes developed KCS
4. using the unaffected eyes as controls, 5.5% of these eyes developed KCS.

There is significant feeling amongst breeders of Neapolitan Mastiffs, Presa Canario and Cane Corso's, (as well as other large breed affected dogs) that excision is a preferable technique to gland replacement. This belief is centered around the fact that the prolapsed gland is so large in these breeds as to cause significant problems in successfully replacing it, and thus repeated prolapse is unacceptably high. Also as these breeds are not high on the list of dogs experiencing KCS, thus the chances of developing this complication are significantly reduced. It is this authors experience that we have had no incidents of KCS in excised glands from these breeds, although it must be stated that this certainly is possible. Some surgeons may choose to cut away some of the gland prior to replacement, and so reduce the likelihood of repeated prolapse, but how that affects the incidence of KCS is uncertain.

Below is a YouTube video of a pocket technique replacement procedure:

http://www.youtube.com/watch?v=xrBSxppLrT4

References:

1. Dr Rhea Morgan, Diplomate ACVIM, ACVO
2. Dr Sherilyn Allen, DVM, Ironstone. USA
3. Schering Plough Animal Health

Dr Mark Rubensohn

Bridlewood Veterinary Clinic

Calgary, Alberta