Just as in humans, pets can develop glaucoma as they age. Glaucoma is a disease of one or both eyes, causing permanent loss of vision in a very short time. The eye is a fluid-filled structure in which the pressure of the fluid within the eye is controlled by both a filling mechanism and a drainage mechanism. Glaucoma is most commonly the result of a dysfunction of the drainage mechanism, causing increased fluid pressure in the eye. The increased pressure can cause damage to tissues within the eye such as the retina and optic nerve, eventually leading to blindness.
Drainage of the fluid within the eye may be impaired due to primary or secondary causes. Primary causes are generally hereditary, and are most often seen in Beagles, Cocker Spaniels, Basset Hounds, Chow Chows, Sharpeis and Samoyeds. Dogs suffering glaucoma due to hereditary causes are more likely to have both eyes affected.
Secondary causes of glaucoma include trauma to the eye, infection of the fluid within the eye, cancers of the iris or ciliary body or corneal ulcers.
The clinical signs of glaucoma depend on the cause as well as whether the condition appeared acutely or over time. Acute glaucoma, which presents very suddenly, is generally very painful. It is accompanied by tearing and squinting, and the fluid within the eye may appear hazy. The pupil may be enlarged, and the eye may appear larger than normal or feel very hard. In chronic cases of glaucoma, the signs may include a change in the color of the iris, watering of the eye, a large eye and blindness.
The diagnosis of glaucoma can only be made by your veterinarian. Using a special device called a tonometer, your veterinarian can measure the fluid pressure of the eye. Your veterinarian can also use an opthalomoscope to determine whether there are any changes to the retina and optic nerve and possibly find the cause of the drainage problem.
For acute cases of glaucoma, your veterinarian may advise that your pet be hospitalized to receive medications intravenously. These medications quickly reduce the intraocular pressure and may prevent vision loss. In more chronic cases of glaucoma, the fluid pressure may be controlled with topical eye medications or oral medications. Depending on the cause of fluid build-up, surgical methods to reduce fluid production may also be considered or recommended. For those pets which have already lost vision in the eye, surgery may be considered to implant a prosthesis or remove the eye altogether.