Unlike humans, dogs actually have three eyelids rather than two – the additional eyelid sitting under the inner corner of the eye. “Cherry eye” is the colloquial term for prolapse of this third eyelid. It can be readily diagnosed upon visual inspection, as a small pink bulge in the inner corner of the dog’s eye. Cherry eye occurs when the tear gland within this (usually hidden) 3rd eyelid, becomes swollen.
Certain breeds of dogs are predisposed to cherry eye and whilst the cause of this condition is not fully understood, there may be a genetic predisposition to its development. Whilst the condition is not likely to be uncomfortable, the tear gland within the third eyelid is crucial to maintenance of eye health. Prompt veterinary advice must be sought with a case of cherry eye, to prevent unnecessary long-term damage.
No prevention is known to exist, however with the appropriate surgery, the condition can usually be successfully treated.
Which dogs can be affected and when?
Symptoms of cherry eye will normally arise in young pets that are less than 2 years of age. As mentioned above, certain breeds are predisposed such as Beagles, Pugs, Boston terriers, English Bulldogs, Cocker Spaniels, Cavalier King Charles Spaniels and West Highland White Terriers. Occasionally the condition may be seen in cats too.
The exact cause of cherry eye remains incompletely understood, however the association with certain breeds of dogs, and other research, suggests in part at least, that a genetic predisposition may exist. Practically speaking in this condition, the third eyelid fails to maintain its usual position within the eye. This may have a possible link and association to defects in connective tissue or associated ligaments. Excitement and shock may also play a predisposing role in some individuals.
Medical treatment: unlikely a solution
Whilst certain medications may be prescribed to help treat cherry eye, ultimately, in nearly all cases, surgery is required. Your vet may temporarily prescribe topical lubricant medication to keep the eye and third eyelid moist and hydrated. Topical antibiotics and anti-inflammatories will treat any associated infection and pain/inflammation respectively. Infection and inflammation should be controlled ahead of surgical correction.
Over the years many different surgical techniques and methods have been employed to treat cherry eye in dogs. What we crucially understand now however, is the essential need to use a surgical technique that accurately replaces and anchors the third eyelid gently back into its usual location, rather than to just excise (chop out!) the eyelid. Surgical replacement offers optimal care to preserve the tear production within the gland. Conversely, if the gland is removed, there is a significant chance of dry eye (keratoconjunctivitis sicca), developing in the eye. This is both a painful and sight threatening condition for the dog and can be an expensive problem to treat.
Surgery should be carried out as soon as possible.
The longer the third eyelid remains prolapsed, the quicker fibrous tissue develops within the gland. Tear production and function will be correspondingly reduced.
Nowadays there are 2 or 3 favoured surgical techniques that can be used to treat cherry eye.
Often, the gland is sewn back into a pocket inside / behind the third eyelid
This method has high success rates. Your vet may be happy performing this themselves in first opinion practice, albeit may also offer referral to a specialist ophthalmologist for the procedure. Any of the techniques utilised, will be performed under general anaesthesia, probably with operating magnifying glasses. It is essential to ensure that the tissues are handled in a delicate, sympathetic and gentle manner.
Whilst success rates are typically good, there is always a small (approximately 10%) risk, of recurrence of the condition. This is not uncommon and will require a second surgery to replace the gland again.
If however, repeated surgical replacements are unsuccessful it may, rarely, become necessary to remove the tear gland entirely.
This should only be offered as a last resort option and if multiples of surgeries have failed to cure the problem. With such “salvage” surgery, the risk for your dog developing dry eye in the long-term, is significant. Your dog will need regular check-ups for this condition, so your Vet can measure the tear production within the eye over a minute, to assess for the adequacy of tear production in the eye.
Follow up post-operative care
Following any kind of ocular surgery, for the first few days, it is vital that a buster collar is worn by the patient. This prevents any unnecessary trauma (and potential wound breakdown) that your dog may inadvertently cause from trying to scratch or rub the wound. The buster collar should stay in place at all times.
Topical post-operative medications are likely to be prescribed (for those reasons stated above) and to minimise any complications associated with the surgery.
Any activities that increase the pressure within your dog’s eyes (such as vigorous playing and energetic exercise), should be avoided. Furthermore, the use of a collar and lead is discouraged, since the force on the dogs’ neck can also act to increase the pressure within the eyes. It is preferable to choose a harness instead.
A small possibility of course, with any surgical procedure, is the risk of complications. Cherry eye surgery is no different. These may include infection, irritation of the eye from the suture material, and as mentioned above, re-prolapse of the gland.
Additionally, if your dog has suffered from cherry eye in one eye, they are at an increased risk of developing this in the other eye.
With an appropriate surgical technique for cherry eye, subsequent development of dry eye should not be a risk.
It should be noted however, that for many of the breeds described as “at risk” or genetically predisposed to cherry eye, there is also a predisposition to developing (unrelated) dry eye (usually bilaterally in both eyes) as middle-aged or older animals. This again, is thought to be attributable to a genetic predisposition, since we frequently recognise “spontaneous” dry eye in these breeds too.
However, for the vast majority of dogs, surgery remains highly successful and provides a permanent solution for treatment of the condition.
Given that a genetic predisposition may exist, it would be a sensible precaution not to breed from any dog affected with cherry eye, for fear of producing further generations of dogs who may be affected with the condition.