Cavalier King Charles Eye Disorders IICAVALIER EYES - PART II

Original Article Written by Myra Ehrman, RN,BA,BS,MScN

on behalf of the Health Education Committee, CKCSCC

This article concludes the series on Care of and Conditions Affecting Cavalier Eyes, which was started in the July, 1996 issue of "Quotes". The first part dealt with an explanation of what happens during a veterinarian eye exam, and also discussed the following diseases and/or conditions which are known to affect Cavalier King Charles Spaniels frequently enough to warrant that owners "keep an eye open" for occurrence in your dogs: corneal dystrophy (aka corneal lipidosis), corneal ulcers, cataracts, distichiasis and other eyelash abnormalities, macroblepharon, and ankyloblepharon.

This article continues with details about other eye diseases which have been identified in the health literature as affecting Cavaliers. This list is by no means exhaustive as to all eye diseases and conditions which can occur; nor should it be assumed that any of these conditions occur with unusually great frequency in Cavaliers. The lists of conditions in both Parts I and II merely highlight those that have affected Cavaliers in sufficient numbers to merit their mention. The article will conclude with additional pointers and reminders on how owners can properly care for their dogs' eyes.

SECOND GROUP OF EYE CONDITIONS

7. Retinal Folds (related to Retinal Dysplasia) - Retinal folds are a form of retinal dysplasia (an abnormality of development) that occur on the retina. Retinal dysplasias are present at birth, and are recognized to occur in three forms:

Folds: defined as linear, triangular, curved or curvilinear foci of retinal folding that may be single or multiple in appearance. They may occur in one or both eyes. Microscopic study of the tissues demonstrates the formation of tubular structures called rosettes. Retinal folds, while they may be a mild form of dysplasia, are also thought to occur through a more benign process of unequal growth rates in the retina and its underlying tissues, the choroid and sclera.

Geographic: defined as any irregularly shaped area of abnormal retinal development (larger areas of true disorganization), representing changes not accountable to simple folding.

Detachment: defined as either of the above described forms of retinal dysplasia associated with separation (detachment) of the retina.

The two latter forms are associated with vision impairment or blindness. Retinal dysplasia is known to be inherited in many breeds, but the genetic relationship among the three forms of the disease is not yet certain. As a rule of thumb, the breeding of dogs with folds only is seen to be at the option of the breeder, whereas the breeding of dogs diagnosed with geographic dysplasia or retinal detachment is not advised.

There is no question that retinal folds occur more commonly in puppies than in adult dogs. According to Dr. Lionel F. Rubin, an American veterinary ophthalmologist, the folds typically occur in certain locations on the retina, are usually not associated with other abnormalities, usually do not progress, and may in fact disappear with maturity. As stated by Dr. Rubin, it has been assumed that the mode of inheritance is recessive (both parents are carriers), and affected animals are not to be considered to have normal eyes. Both affected and unaffected dogs have been seen in litters with unaffected sire and dam. In his opinion, if the condition is to be eliminated, affected individuals should not be bred. He does note that as vision is not thought to be affected, the condition can be considered to be a blemish, and should not by itself cause the removal of an otherwise sound animal from one's breeding program. As one writer on the internet wisely noted, if a breeder does choose to breed a bitch who has folds (or was known to have them as a puppy), that breeder would be wise to ensure the male used not only is clear of folds at the time of mating, but also had been given an eye examination at about one year of age (or less) which also showed him to be clear of folds.

Interestingly, Cynthia S. Cook, DVM, PhD, has written that animals with folds alone will be issued CERF (Canine Eye Registry Foundation - see Appendix for more detail) numbers, EXCEPT the Samoyed, Labrador retriever, and English Springer Spaniel; in these breeds, there is definite genetic evidence that the folds alone may represent a significant genetic entity.

8. Progressive Retinal Atrophy - Abbreviated PRA; this disorder is sometimes also known as Progressive Retinal Degeneration (PRD). According to the internet web site (http://www.netrover.com/~eyevet/pra.html) provided by Dr. Michael Zigler, ophthalmologist in practise in Oakville, Ontario, in all animals with PRA, the outcome, age of the dog, and what the veterinary ophthalmologist sees are the basis for the classification of exactly what type of condition the patient has. This particular condition has been seen in almost every registered breed and in mixed breed dogs as well, although it is an unusual condition to affect Cavaliers.

As the name implies, a slow death of the retinal tissue takes place. The disease progresses gradually, and the earliest signs may be overlooked, as it is not a painful condition. The earliest signs include night vision difficulties that in most cases will progress to day blindness. Dogs may appear to be disoriented when going out in their yards at night, or may be afraid to go into a dark room. Other behavioural changes may be noticed later, such as a dog being willing to go up, but not down, stairs. Some owners may notice an abnormal shine coming from the dog's eyes; this is due to the pupils being dilated and not responding as quickly to light as do pupils of normal dogs. Cataracts may occur and generally occur later in the disease. Diagnosis is confirmed when a test called ERG is given; the dog is anesthetized and a special instrument is used. There is no known treatment for this disorder.

Dr. Rubin has indicated that while the mode of inheritance has not been positively established, it is assumed the condition is recessive. It is recommended that not only should the affected dog be withdrawn from any breeding programs, but so should both parents and all littermates.

9. Excessive tear staining - Blockage of tear-ducts will lead to an overflow of tears from the inner corner of the eye. While most obvious in white-faced dogs, because the overflow of tears leads to tear staining, as Cavalier owners know, this is not an uncommon problem in our breed. The problem is that while the dog's tears are secreted in normal amounts, they are not adequately drained away (nasolacrimal occlusion). Small or absent tear-duct openings will lead to this condition, but it can also occur if the ducts are blocked with pus or mucous during eye infections. If there is an inflammation, redness and/or signs of discomfort will be seen, along with increased tear production. Other possible causes include scarring of the ducts or their openings, or a foreign body (such as a grass seed) becoming lodged anywhere in the drainage system.

Blocked tear-ducts may be diagnosed by placing a drop of fluorescein dye onto the surface of the eye. If the tear-ducts are normal, green drops will appear at the nostrils within a short period of time; failure of the dye to appear indicates there is a blockage in the corresponding duct.

Surgical intervention may be attempted, although if the duct openings are absent, very little can be done. If the openings are present, special probes may be used and various flushing techniques are tried to highlight the site of obstruction. Often the flushing techniques in themselves remove the problem. Antibiotics and steroids may be required to reduce the inflammation.

10. Conjunctivitis - As in people, this is an inflammation of the conjunctiva. It is very common in dogs, and causes the white of the eye to appear red. It can vary from mild to very severe. When the condition is mild, the only observable symptoms may be a slight redness and irritation with increased tear production. When the condition is severe, the eye is very red and painful, and there will be considerable discharge, which may vary from watery to a thick, grey/green pus. The eyelid may be closed (blepharospasm), and the dog will not like having its eye examined.

Causes can include viruses, bacteria, chemicals, allergies, trauma, or foreign bodies. If both eyes are affected, it might mean there is a more general disease process underway. The usual treatment is to bathe the eyes with warm sterile water and to apply antibiotic and/or anti-inflammatory drops or ointment. If the owner has eye medications left over from other episodes, and wants to start treatment immediately (don't these things always start at 11 p.m. Saturday night on a holiday weekend?), be sure to honour the following cautions: 1) check the expiry date (usually on the label for drops and on the crimp of the tube for ointments) and discard any medication that is past that date; 2) never use medication that include anti-inflammatory drugs (cortisone) without a veterinarian's authorization (you can do more harm than good); 3) never allow the tip of the medication bottle or tube to touch the dog's infected eye; 4) wipe each eye with clean tissues (don't reuse); and 5) if no improvement is seen within a day or two, don't lose any more time getting an appointment with your vet.

11. Cherry Eye - This condition occurs when the tear gland on the inner surface of the third eyelid enlarges due to infection. As swelling occurs, it is forced out from beneath the lid, exposing a red, cherry-like growth at the nasal corner of the eye.

The usual recommended treatment is surgery. The author of this article had personal experience when one of our Cavaliers developed the condition a few years ago. Before signing our dog up for the surgery, some good old-fashioned nursing care was applied. Using a clean washcloth each time, warm (not hot) compresses were very gently held in place on the dog's eye for 15-20 minutes, four times a day, for about four or five days. Following each session with the warm, moist compress, the prescribed antibiotic was applied (as outlined under the conjunctivitis section). To our vet's amazement, the condition responded to the treatment, and no surgery was needed. Although we were advised the condition is prone to recurrence, so far it has not happened again.

12. Blindness - There are many individual conditions which can lead to blindness. They include diseases of the cornea (keratitis), the lens (cataract), increased pressure within the eye (glaucoma), any disease which reduces retinal sensitivity to light impulses (retinal atrophy), or any disease which affects the optic nerves or the sight-center of the brain (tumours, trauma).

Some signs which might alert owners that a dog is not seeing as well as it should include uncertainty as to where it is going, treading on articles usually avoided, bumping into furniture, and carrying the nose low to the ground. Shining a bright light into a dog's eyes to see if the pupils constrict is not by itself diagnostic. Senses of hearing and smell can become more acute as vision starts to go.

The literature makes many suggestions as to how owners can deal with blind pets. While most of them are based on common sense, they are worth repeating here. First and foremost, when out of doors, keep the dog on a leash or in a familiar fenced yard. If there is a hot tub or pool on the property, a cover or barrier is needed to prevent the dog falling in and drowning. Keep the food and water dishes in exactly the same places every day; the area can become a site for reference if the dog becomes disoriented. Don't rearrange the furniture, and be careful about putting chairs back under the table when finished eating. Place a barrier at the top and bottom of stairs; going up and down stairs has to be re-learned by the blind dog. If you know the dog is losing its sight, take the opportunity to teach it some verbal commands, such as "stay", "wait", and "down" if it doesn't know any; such obedience training might save its life one day.

A FEW LAST EYE CARE COMMENTS

Cavalier owners know our dogs are treasured for their soft, melting facial expressions, and that their large, round, dark, protuberant eyes contribute to the classic Cavalier look. It also means that we have to take special care of these very important Cavalier assets.

Earlier in 1996, there was a discussion on the Spanie-l computer mailing list about why Cavaliers do not make good field dogs. They were never bred to be retrievers or hunters; they were bred to be companion dogs. While many enjoy accompanying their owners on hikes in the woods, care needs to be taken that the paths are not too narrow and do not have a lot of low-hanging bramble, as their eyes are more vulnerable than are those of many other breeds. Even in their own backyards, ensure they will not poke their eyes on newly pruned shrubbery. One of the most common causes for dust, dirt, vegetable matter, etc. to get into dogs' eyes is allowing them to ride in the car with their heads out the window; for Cavaliers, this method of transport is asking for trouble. So is taking an extra long walk on a very windy day.

If it has been determined that the dog does in fact need medication, here are some final pointers. First, make sure your hands are well washed both before and immediately after applying the medicine. (If the infection is particularly stubborn or messy, using disposable paper towels to minimize risk of cross-contamination is a good idea. Use a clean paper towel to turn on the tap after handling the dog's eyes, dispose, and use another clean paper towel to dry your hands.) When applying the medicine, pull the lower eyelid down and apply the ointment to the inner surface of the eyelid (the dog will try and pull away if you attempt direct application of ointment). Eyedrops may be applied directly to the eyeball; you may now gently rub the eyelid to spread the medicine. Do not assume minor eye problems will clear on their own, otherwise you may find yourself treating major eye problems.

The author has not specifically researched which preparations are most satisfactory for routine eye care, to minimize the effects of tear staining and to otherwise keep the dogs' eyes neat and tidy. Owners are invited to write "Dear Gabby", CKCSCC "Quotes" newsletter, care of Dan Boyce, 55 Maitland St., Apt. 1003, Toronto, Ontario M4Y 1C9, or e-mail at dboyce@ftn.net if you have a particular brand or method you would like to recommend.

Please see the Appendix immediately following this article, which outlines in more detail how CERF would rate different conditions.

CKCSCC members residing in southern Ontario are reminded that the next CFSO eye screening clinic will be held on Saturday, November 2, 1996 this year.

APPENDIX

EYE DISORDERS AND BREEDING ADVICE FOR

CAVALIER KING CHARLES SPANIEL

Reprinted with permission, American College of Veterinary Ophthalmologists.