Glaucoma-- can your pet go blind?

Glaucoma has been, and will remain, one of the leading causes of blindness in dogs and cats. In the initial stages of glaucoma, the patient has no pain and only a mild change in the appearance of the eye. The sclera (or white part of the eye) may appear "bloodshot" and the patient may seem a little extra sensitive to bright light. As the disease progresses the patient may have noticeable pain, although the source of the pain may be difficult to localize. The eyeball itself may appear swollen at this stage of the disease. If left untreated, the patient will lose eyesight, sometimes becoming blind quite suddenly. Some cases can progress to complete blindness in a very short period of time.

How is glaucoma typically caused? The front part of the eye-from the cornea to the lens-is filled with a fluid called aqueous humor. It produced continually by the eye. This production is offset by continuous reabsorption of aqueous humor into the blood stream through an area of the eye known as the drainage, or filtration, angle. The delicate balance between production and reabsorption of aqueous humor maintains the normal size and shape of the eye. Glaucoma, an increase in pressure within the eye, results when there is normal production but decreased outflow of aqueous humor. (Click on drawing for complete illustration.)

Most clients are aware of routine glaucoma testing, as optometrists and ophthalmologists usually do this at the time of eye examinations. We have a specialized piece of equipment, the same one that the ophthalmologist use, that greatly enhances the ease and accuracy of glaucoma screening. The test is very safe and comfortable for the patient. A topical anesthetic is applied to the eye and the tonometry instrument is gently tapped on the cornea (the clear covering on the front of the eye). Sanitary tip covers are used to avoid any contamination. The owner can calm the patient if anxious, although this is rarely necessary. The entire procedure takes only a few minutes and is safe and accurate. If an elevated pressure is noted, an appointment can be made to discuss the results with the veterinarian. The doctor may advise a complete physical exam as well as additional testing. In most cases your veterinarian will refer you and your pet to a veterinary ophthalmologist.

Any pet can benefit from routine glaucoma screening. It is a good idea to know your pet's normal ocular pressure measurement. There are also certain breeds of dogs and cats that are predisposed to glaucoma. These pets should have a baseline established and monitored on an annual basis. If a history of glaucoma is already in the bloodline, these pets should be monitored more frequently. Screening for glaucoma is also very important in senior pets and should be done on an annual basis beginning at six to seven years of age. Early detection is the only way to aid in the control of glaucoma.

Find out more about tonometry to detect glaucoma.

Some cat breeds with a predisposition are:
Persians
Siamese
Some Domestic Shorthairs