Eye disorders account for a large number of visits to the clinic because they are amongst the easiest problems to recognize and always appear potentially worrisome.
Understanding the signs
Check with your vet if you notice any of the symptoms below: they may simply indicate an allergy, but can also be caused by more serious concerns, such as corneal damage.
- Discharge and cloudiness;
- Redness or inflammation;
- Visible third eyelid;
- Tear overflow;
- Bulging or sunken eye;
- Crust or inflammation around eye;
- Deterioration or loss of vision;
- Increased irritability and pain.
Damage to the eye, through fighting or due to an accident, is one of the most common reasons for blindness, especially in flat-faced breeds like the Pekingese, in which the eye is not deeply recessed. Damage to the cornea – the outermost layer of the eye causes swelling and produces a cloudy appearance, and corneal abrasions can develop into ulcers. Your vet will clean the eyes and treat with appropriate antibiotics, but in extreme cases, surgery may be needed.
A cataract is the loss of transparency to part or all of the lens, and is another common cause of blindness. Cataracts in one eye only can be triggered by physical injury, but if they appear in both eyes, the most likely explanation is late-diagnosed sugar diabetes or a genetic predisposition (especially in Labradors and Cocker Spaniels). Cataracts can be surgically removed, but only when they cause complete blindness and there is no associated degeneration of the retina. Careful breeding is the only way to reduce the risk of inherited cataracts. The condition may not develop until a dog is six years of age, so before breeding from a dog, check that its parents, grandparents, and great-grandparents are known to be free from hereditary cataracts.
In youth, the lenses of the eye are flexible and clear, but with aging they become hardened, hazy, and blue-grey, and can begin to resemble cataracts. This natural change, called “sclerosis”, is seen in dogs over nine years of age, and does not require treatment.
Progressive retinal atrophy (PRA) This inherited eye condition is recognized in over 90 breeds. Symptoms of the disorder usually begin with night blindness, and progress to lack of confidence when jumping or walking down stairs. Complete blindness is usually inevitable and there is no treatment. As with hereditary cataracts, there are examination schemes to certify that breeding individuals are free from PRA. DNA tests are available for breeding stock in breeds including Labradors, Cocker Spaniels, and Poodles.
Other eye conditions
Reduced tear production causes “dry eye” or keratoconjunctivitis sicca. The most common cause, particularly in West Highland White Terriers, is an immune-mediated disease. Eyes lose their lustre and there is often an accompanying purulent conjunctivitis. The condition responds well to cyclosporin ointment. The iris and front chamber of the eye can be affected by infectious diseases, such as leptospirosis. The iris of an affected dog becomes inflamed (uveitis), and the pupils may constrict. Other signs include red eyes, squinting, avoidance of light, and excess tear production. In severe cases, blindness can result. Treatment is generally with antibiotics and corticosteroids.