Effects of Glaucoma
Glaucoma refers to elevated pressure inside the eye that causes vision impairment and, if left untreated, blindness due to degenerative damage to the retina and optic nerve. The clinical signs of canine glaucoma are fairly nonspecific and change over time depending on the stage of the disease. Many owners do not realize that their dog is suffering from glaucoma until the condition has progressed to an advanced stage. However, subtle changes in the appearance of the eyes can provide an early warning that glaucoma is present.
Symptoms of Glaucoma in Dogs
Owners may notice one or more of the following signs of glaucoma in their canine companions:
- Eye redness
- Eye cloudiness
- Abnormal ocular discharge
- Stumbling over or bumping into normal objects
- Excessive barking
- Behavioral changes associated with pain
- Lack of appetite (anorexia)
- Bulging eyes (buphthalmia)
- Large (dilated) pupils
- Pawing at or rubbing the eyes or face
- Aversion to being petted or touched on the face or around the eyes
- Extreme sensitivity to or avoidance of bright or direct light (photosensitivity)
most cases, glaucoma appears first in one eye, and a short time later appears in the other. Other early signs of glaucoma involve changes to the appearance of the pupil, which may be dilated (larger than usual) and may not contract quickly when exposed to light. Vision loss normally is not noticed by pet owners. However, if a dog’s vision has been dramatically affected by the disease, owners may notice that their dog stumbles over objects in its path, barks more often than usual or bumps into the corners of walls and doorways. In advanced stages, glaucoma causes the affected eye(s) to bulge, called globe enlargement, “buphthalmos” or “hydrophthalmos,” and the eyes may take on a greenish sheen. Treatment is necessary to prevent permanent eye damage, pain and blindness.
Dogs at Increased Risk
There is no particular age or gender predisposition to the development of glaucoma in dogs. While it can occur in any breed, certain breeds are predisposed to this condition, including some spaniels (the American and English Cocker Spaniel, English and Welsh Springer Spaniel), Basset Bound, Beagle, Chow Chow, Chinese Shar-Pei, many terriers (including the Boston, Wire Fox, Cairn, Manchester, Dandie Dinmont, Norfolk, Norwich, Scottish, West Highland White and Parsons Jack Russell), some arctic breeds (the Norwegian Elkhound, Siberian Husky, Malamute, Akita and Samoyed), retrievers (Flat-Coated and Golden), Bouvier des Flandres, Maltese, Shih-Tzu and Miniature Poodle. Many other breeds have been reported to suffer from primary or secondary glaucoma, as well. Dogs with glaucoma often exhibit behavioral changes attributable to pain.