Aware Owners Can Slow Glaucoma

Q. Can and should dogs be routinely checked for glaucoma? Is this something a regular veterinarian should do, or must the dog go to a specialist?

A. Glaucoma results from fluid accumulation that leads to excessive pressure inside the eyeball, known as intraocular pressure or IOP. Many conditions can cause abnormal flow of the fluid (aqueous humour) inside the eyeball. Excessive fluid accumulation leads to pressure buildup. This may occur suddenly or over a prolonged period and depends on the cause, with secondary glaucoma developing suddenly because of a different disease and primary glaucoma usually developing slowly as a genetic condition. If left untreated, damage occurs to the sensitive retina and other structures of the eye, leading to blindness, varying degrees of pain and degeneration of the eyeball.

All dogs, especially breeds prone to glaucoma, should have their eyes examined at their annual physical exam. Early, subtle changes may be noted. The low incidence of glaucoma negates the need for routine pressure testing of all dogs. Most glaucoma cases have a clear indication for checking the intraocular pressures; furthermore, most acute cases - those that develop suddenly - probably had normal pressures prior to the onset of visible symptoms and would not have been recognized.

Any dog with suspicious changes should be re-evaluated more frequently. Closely follow your veterinarian's recommendations. Twice-yearly physical exams are a good idea for middle-aged and geriatric dogs. Dogs with significant cataract development are potential candidates for topically administered anti-inflammatory medications. Discuss this with your veterinarian.

Owners with potential breeding animals and those who want greater peace of mind should consider an early visit to the ophthalmologist for a complete evaluation of the fluid outflow tracts and internal eye structures. This will allow the earliest possible detection of glaucoma or the tendency toward it. The most important link in identification and early treatment of this potentially devastating disease is owner awareness.

Primary, genetic glaucoma affects many breeds, though it doesn't occur very often. Structural changes in the fluid outflow tracts lead to slower fluid flow from inside the eye. This form of glaucoma tends to develop slowly as a chronic condition, though acute flare-ups do occur. Generally both eyes will be affected, though the symptoms may develop at different times in each eye. The condition affects spaniels, Chow Chows, Chinese Shar-Peis, Basset Hounds, toy breeds (Poodle and Shih Tzu) and Arctic Circle breeds (Samoyed, Akita and Siberian Husky). While breed predispositions exist, no dog is immune to the possibility of developing primary glaucoma.

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