Glaucoma is a condition associated with elevated pressure within the eye. The fluid which fills the eye is constantly being produced, circulates around the lens, and exits the eye through the iridocorneal angle (see drawing). The balance between fluid production and outflow results in normal intraocular pressure between 10-30 mm Hg. Elevation in intraocular pressure occurs as a result of poor fluid outflow.
Glaucoma most commonly occurs as a primary inherited disease in many breeds of dogs particularly the Cocker spaniel, Basset hound and Chow. Inadequate fluid outflow may also occur from secondary causes such as dislocation of the lens, trauma, inflammation, or tumors. In these cases, treatment will be directed at the primary disorder.
The prognosis for vision in an eye with glaucoma depends on the degree and duration of elevated pressure. Irreversible damage to the retina and optic nerve may occur within a day or two if the pressure is markedly elevated. If only one eye is involved, your pet may compensate for his loss of vision until permanent damage has occurred in the involved eye. Since glaucoma will often ultimately affect both eyes, evaluation of the “normal” eye is very important. Gonioscopy is an examination of the iridocorneal angle that will assist in this evaluation.
Treatment for glaucoma depends on whether permanent vision loss has occurred. In early cases, medications may be given to lower the pressure immediately. However, rarely is medication alone successful in the long-term. In most cases, surgery offers the best opportunity to restore and maintain vision. Laser cyclophotocoagulation is a relatively new technique which uses a diode laser to burn small areas in the tissue in the eye (ciliary body) which produces fluid so that less fluid is produced. This procedure has the advantages of being relatively quick with minimal post-operative discomfort. Results are variable though and occasionally, more than one procedure may be required. Some cases require a combination of medical and surgical management and all cases require close clinical supervision. You should watch for signs of loss of vision, pain, or a cloudy appearance to the eye.
If it is determined that vision cannot be restored, treatment is directed at relieving discomfort and achieving optimal appearance. Options for management of pain include.
Intraocular prosthesis: a surgical procedure where the contents of the globe are replaced with a sphere which retains the shape and general appearance of the eye.
Ciliary body ablation: techniques used to decrease intraocular fluid production; these include Laser cyclophotocoagulation and Chemical ablation
Enucleation: surgical removal of the eye with closure of the eyelids
You will be given information about these options as they apply to your pet’s condition.
In some cases, both eyes are affected and vision may be permanently lost.
Can Blind Pets Lead Healthy Lives? Absolutely YES!
Glaucoma is a challenging disease – successful management requires close cooperation between you and your pet’s ophthalmologist. Please feel free to ask questions at any time during treatment.