How Blindness Affects Dogs
Blindness can affect one or both eyes. If it affects only one eye, it is called unilateral blindness. If it affects both eyes, it is considered to be bilateral. Blindness in domestic dogs can come on suddenly or very gradually.
Symptoms of Blindness
The symptoms of vision loss often include one or more of the following:
- Bumping into objects or structures in the dog’s own environment
- Vision deficits in dim light and darkness (loss of “night vision”)
- Difficulty finding food bowls, water dishes, toys and other familiar things
- Difficulty catching balls or other objects
- Exaggerated high-stepping gait
- Walking with great caution
- Walking with nose to the ground
- Reluctance to move
- Redness of the eye(s) (+/-)
- Dilated (enlarged) pupils (+/-)
- Opacity of the eye(s) (+/-)
Dogs whose vision loss happens gradually tend to adjust better and compensate better than those with a sudden onset of vision deficits, especially if the vision loss is very slowly progressive.
Dogs at Increased Risk
Dogs (and cats) of any age or gender may be affected by blindness, depending upon its cause. Some breeds have an increased risk of developing blindness due to primary glaucoma, including the Beagle, Bassett Hound, Bouvier des Flandres, Chow Chow, Cocker Spaniel, Dachshund, Dalmatian, Great Dane, Poodle, Shar-Pei, Malamute, Siberian Husky and certain Spaniel breeds. When the cause of blindness is lens luxation, the breeds at increased risk include Terriers, Spaniels, German Shepherd Dogs, Miniature Poodles, Toy Poodles and Chihuahuas. When blindness is caused by retinal detachment, Shih Tzu’s seem to be at increased risk.
Older dogs tend to be predisposed to developing blindness associated with cancer (neoplasia) and retinal detachment. Dogs with frequent access to the out-of-doors may be predisposed to developing infectious diseases and/or trauma associated with vision loss. Dogs with poorly-regulated diabetes mellitus are predisposed to developing cataracts, which can contribute to blindness. Dogs with hypertension (high blood pressure) are at increased risk for developing retinal detachment and corresponding vision loss.