Glaucoma is a disease characterized by increased fluid pressure within the eye. Healthy eyes continually produce and drain this fluid, called aqueous humor, to maintain a constant intraocular pressure (IOP). If the drainage network becomes obstructed, IOP increases significantly, causing extreme pain and often blindness.
Risk factors and detection
Primary glaucoma is a hereditary disease in which the drainage angle is defective, resulting in gradual blockage. Signs usually first appear in middle-aged dogs, but dogs of any age can develop glaucoma. Typically, disease progresses in one eye—then the other.
Dog breeds predisposed to primary glaucoma include Basset hounds, Bouviers des Flandres, chows, Maltese, Shar-Peis, Shih Tzus, spaniel breeds, Toy poodles, and Arctic breeds, such as Akitas, Alaskan malamutes, Norwegian elkhounds, Samoyeds, and Siberian huskies.
Secondary glaucoma occurs when another condition, such as lens dislocation, eye trauma, or inflammation, blocks the drainage network. This disease affects dogs of all ages.
Signs of disease include:
- squinting or keeping one eye closed
- obvious eye discomfort or pain
- a swollen, hard eye
- tearing
- inflamed or red eyes
- a cloudy cornea
- vision loss.
If you notice any of these signs, call your veterinarian. Glaucoma is a medical emergency requiring immediate care. Increased pressure can damage the retina and optic nerve, resulting in permanent blindness in a matter of hours. The faster your veterinarian detects and reduces the pressure, the better chance your dog has to recover with his vision intact.
To detect glaucoma, your veterinarian will measure the pressure in your dog's eye, and he or she may refer you to a veterinary ophthalmologist for more advanced diagnostic tests and treatment.
Prevention and treatment
You can't prevent glaucoma, but if your dog is predisposed to the condition, periodic eye examinations may identify early signs. Always report any physical or behavioral changes to your veterinarian, especially if your dog already suffers from glaucoma in one eye. One simple way to reduce the prevalence in dogs: Don't breed dogs with primary glaucoma.
When treating this condition, your veterinarian's priority is to rapidly reduce the IOP. He or she will use medication to open the drainage angle, reduce fluid production, and remove fluid from the eye. If the eye responds, you can administer oral medication and eye drops at home. If your dog is diagnosed with secondary glaucoma, your veterinarian also will need to treat the condition that's increasing the IOP.
After IOP is stabilized, sighted dogs will need surgery to improve drainage or reduce fluid production. Veterinary ophthalmologists perform these surgeries.
If your dog's eye is blind and painful, your veterinarian likely will recommend removing it. Before your dog's surgery, ask the doctor to explain all treatment options, including the use of a prosthetic eye.
Prognosis
Even with treatment, more than 40 percent of dogs with glaucoma become blind in the affected eye within the first year. The good news: Blind dogs typically adapt quickly to their condition and lead normal, happy lives.
