Canine Glaucoma
Canine glaucoma, like human glaucoma, is a serious disease that may result in blindness. Canine glaucoma is categorized as either primary or secondary. Primary glaucoma is a genetic disorder affecting certain breeds, most commonly beagles, cocker spaniels, basset hounds and Samoyeds. In contrast, secondary glaucoma is a complication of another eye disease or trauma, such as uveitis or lens displacement.
Normally, eye fluid known as aqueous humor flows from the ciliary body where it is produced out through a drainage canal. When fluid is produced more quickly than it can exit the eye, glaucoma occurs, resulting in increased pressure inside the eye, known as intraocular pressure. When intraocular pressure is too high, the optic nerve and the retina undergo deteriorative changes.
Symptoms of Canine Glaucoma
Depending upon how rapidly signs of the disease develop, glaucoma can be diagnosed as acute or chronic.
Acute Canine Glaucoma
The symptoms of acute glaucoma are:
- Intense pain
- Tearing
- Squinting
- Hardening of the eye
- Fixed blank look
The fixed blank appearance of the eye affected with acute glaucoma is the result of an enlarged pupil and a misty cornea.
Chronic Canine Glaucoma
Once canine glaucoma becomes chronic, not only is the affected eye harder than the other eye, but the eyeball visibly protrudes from the eye socket. Almost always, by the time the chronic stage has been reached, the affected eye is blind.
Diagnosis of Canine Glaucoma
Canine glaucoma is diagnosed by an eye examination and a measurement of intraocular pressure. Both of these tests must be performed by a qualified veterinarian.
Treatment of Canine Glaucoma
Treatments of canine glaucoma differ according to the category of the disorder. In the case of secondary glaucoma, the underlying eye condition must be treated.
Treatment of Acute Canine Glaucoma
Because acute glaucoma can result in blindness in only hours, it requires urgent veterinary care. When eye pain or other symptoms are present, immediate veterinary treatment should be sought. Acute glaucoma is treated with medications that will rapidly reduce intraocular pressure. Some medications are administered orally, others intravenously. Topical medications may also be administered to increase fluid outflow.
When medications do not have the desired results, a surgical procedure may be required to reduce intraocular pressure. Such an operation will require treatment at a special canine eye center.
Treatment of Chronic Canine Glaucoma
When a dog suffers from chronic glaucoma and the affected eye is blind, that eye may be susceptible to corneal injuries and the animal may be in severe pain. In such cases, the affected eye must be removed. When this happens, a prosthesis is sometimes inserted for cosmetic reasons.
Prevention of Canine Glaucoma
All dogs with a genetic predisposition to primary glaucoma should be examined annually for signs of elevated intraocular pressure so that treatment can be begun preventatively if necessary. Since in about half of all cases of canine glaucoma, when one eye is affected, the second eye develops glaucoma within 2 years, any dog with glaucoma in one eye should be carefully watched for signs of the disease in the other eye. Such an animal may need to be checked several times a year.
Because It has been demonstrated that the pull of a neck collar can increase intraocular pressure in an animal with thin corneas, any dog suspected of being prone to glaucoma should be walked with a harness rather than a collar.