Article Category: Pet Eye Disorders
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Glaucoma

(Added on March 25, 2008)

Glaucoma in its simplest definition is an increase in the intraocular pressure (IOP) which leads to damage to the delicate nerve tissue (optic disc and retina) inside the eye. To better understand how this occurs you need to know how normal intraocular fluid (aqueous humor) flows through the eye and maintains normal pressure.

Aqueous humor is produced by the cilliary body, a structure behind the iris (colored portion of the eye). The fluid flows forward through the pupil and into a sieve-like drain at the junction of the cornea and iris (iridocorneal cleft). The production of aqueous humor and the drainage occur at approximately the same rate resulting in a stable pressure inside the eye.

Whenever the drainage area becomes "clogged" or "blocked" the fluid pressure builds up inside the eye. The resulting high pressure compresses the optic disc fibers and retinal tissue and blindness results.

Primary glaucoma is known to occur as an inherited condition in certain breeds of dogs including: Spaniels, Terriers, Beagles, Basset Hounds, Norwegian Elkhounds, Chow Chows, Arctic Circle Breeds (Siberians, Samoyeds, Malamutes) and the list is growing.

Secondary glaucoma is the result of some other intraocular condition that interferes with the normal flow of aqueous humor such as: intraocular inflammation (uveitis), hemorrhage, lens dislocation, tumors, and/or trauma to the eye.