Introduction
Treatment of glaucoma in dogs varies based upon the underlying cause of the condition. However, treatment normally involves application of topical eye medications and/or surgery.
Treating Glaucoma in Dogs
The goal of glaucoma therapy is to lower the intraocular pressure of affected eyes in order to maintain vision as long as possible and eliminate pain.
Medical Therapy
Regardless of the cause, most cases of canine glaucoma are initially treated with some combination of topical and systemic medications designed to decrease intraocular pressure. A number of prescription drugs are available to dehydrate the aqueous humor (the fluid inside the eye), reduce the production of aqueous humor and/or increase the normal drainage of aqueous humor from the eye.
Topical corticosteroids also may be used, provided that corneal ulcers are not present (because in addition to their anti-inflammatory effects, steroids can delay tissue healing). If only one eye appears affected by glaucoma, the other eye (called the “fellow eye”) can be treated prophylactically; this seems to delay the onset of glaucoma in the fellow eye for several months or even longer. New medications are always in development, and only a veterinarian can determine which of the available drugs to use in any given situation. In all cases, dogs with glaucoma should be reevaluated regularly in order to track intraocular pressure and make necessary adjustments in medication. Medical treatment is usually life-long and can be quite expensive. Unfortunately, with drug therapy alone, most dogs with primary glaucoma will eventually go blind.
Surgical Therapy
A number of surgical procedures are available to manage glaucoma, although none of them have been highly successful. The goals of glaucoma surgery are to increase the outflow of aqueous humor, decrease its production, maintain vision as long as possible and resolve ocular pain. Surgical options include placement of small implants (called shunts) into the eye and/or using laser therapy (called cyclophotocoagulation) to promote fluid drainage, reduce fluid production, prolong vision and reduce pain. Another procedure involves the injection of certain drugs into the eye to damage or destroy the cells that produce the aqueous humor. Surgical removal of the lens in affected eyes is also possible.
In most cases, these surgical procedures only slow the progression of the disease, and the eyes often develop irreversible scarring and eventual vision loss despite surgery. Once glaucoma progresses to blindness, or if medical pain management is unsuccessful, there are several surgical salvage options. The globe can be surgically removed (called enucleation) or it can be eviscerated, which involves removing the contents of the eyeball while leaving the tough, usually white outer part of the eye, called the sclera, intact. These procedures will remove the source of severe, chronic pain that accompanies end-stage glaucoma. Prosthetic implants are available as well, for a result that is cosmetically acceptable to owners.
Outlook for Treating Glaucoma in Dogs
The success of any glaucoma treatment depends heavily upon how early the condition is diagnosed, and whether it is primary or secondary to another problem. The prognosis for the first eye affected by glaucoma is normally poor, regardless of the treatment protocol, because by the time of diagnosis the disease is usually advanced and nonresponsive to medical therapy. Preventative (prophylactic) medical treatment of the fellow eye can be helpful in delaying the onset of glaucoma for many months.