Dog eye diseases are oftentimes genetic, however others are the natural result of aging. Many eye problems are associated to the loose skin of the face, which happens in mixed breeds and purebreds alike. Traumatic eye diseases are sometimes caused by hereditary characteristics, although they might not always be related to genetics.
Progressive Retinal Atrophy:
Progressive Retinal Atrophy (PRA) is a serious hereditary eye disease caused by the deterioration of retinal cells, resulting in the dog not being able to see stationary objects. It causes vision impairment by about five years of age. Purebred breeding stock should be tested for this disease. Ask your veterinarian about the various certifying agencies such as CERF. Some affected dogs are treated, however cure is unlikely. A dog affected with PRA can lose his vision, but blindness isn’t fatal. If the vision decreases slowly, the dog can adapt and live a normal life as a pet.
A dog may inherit a predisposition for this condition, which may cause symptoms at any age. It’s not a serious threat to the life of the dog, but if it’s determined to be hereditary, affected dogs should not be bred. Entropion is caused by excess skin around the dog’s eyes, which causes the lids of the dog’s eyes (upper or lower) to roll inward. With the rolling skin, the hair of the eyelids rubs on the dog’s cornea, causing severe irritation. Secondary conjunctivitis generally accompanies entropion, and the dog often squints in discomfort. This condition is easily fixed by a comparatively simple surgical procedure.
Ectropion is another surgically correctable eyelid problem. If too much loose facial skin causes the eyelids to sag excessively, the exposed conjunctiva is subject to infection. Predisposition for this condition is sometimes inherited, but may occur in mixed breeds.
Corneal Scratches and Ulcers:
These are usually traumatic in nature, though in some breeds ulcers can occur spontaneously and are considered to be genetically transmitted. Simple dust irritation or foreign bodies such as grass seeds that are picked up under the eyelids often cause dogs to scratch and rub at their eyes. Toenails can cause corneal scratches as well. Prompt diagnosis and treatment is needful. If unattended, the dog’s constant scratching could cause the cornea to tear, and loss of sight ensues, sometimes followed by a loss of the eye. Whenever the dog squints, rubs his eyes, holds it closed, and it looks reddened and inflamed, rush him to your veterinarian.
The nictitating membrane, also called the third eyelid, usually appears as a tiny pink structure located at the inside corner (nasal canthus) of the eye. If that membrane becomes irritated, it spreads out over the entire eye surface. If the gland located on the underneath side of the membrane becomes inflamed, it will swell and cause the whole third eyelid to turn wrong-side-out. This results in a horrible-appearing red mass, which, amazingly, doesn’t appear to bother the dog in the least. Cherry eye is easily diagnosed, and if no cause is determined, can be treated either by surgical removal of the gland or occasionally by medication to combat the swelling and infection. A predisposition for cherry eye can be inherited.
Normally a condition found in older dogs, cataracts may be hereditary. A cataract is an opacity within the lens, which lies directly behind the iris. Eventually causing blindness, this condition can’t be treated medically. Cataract or lens removal is surgically possible. Surgery is expensive, and even when performed by specially qualified veterinary ophthalmologists, it could have complications.
This disease is often genetically transmitted. It results when the fluid pressure within the eyeball increases, causing significant discomfort and possible blindness. Glaucoma is diagnosed with special veterinary equipment and is treated both medically and surgically with fair success.
Pigmentary Keratitis (PK):
A condition caused by the invasion of blood vessels into the normally clear cornea, PK is usually genetically linked with certain breeds. German Shepherds are probably the breed in which this disease is encountered most frequently. Invading vessels transport pigment into the cornea and deposit it there, and if allowed to advance unchecked, PK will in time cause a physical blockage to vision. The invasion of blood vessels can usually be controlled by the application of medication into the eye, or by injecting steroids into the critical point between the cornea and sclera (white) of the eye.