What is Glacoma?
Glaucoma is an ocular condition relating to increased pressure within the eye of a cat or a dog. If this intraocular pressure gets too high or remains consistantly elevated, damage to the structures within the eye will result,leading to eventual blindness. Healthy eye tissue produces and eliminates fluid naturally. This fluid, referred to as aqueous humor, is normally created and eliminated at a constant rate, allowing the eye to stay in it's natural round state. However, the fluid pressure increases if the tiny pores in the eye become blocked, causing an imbalance in this natural ebb and flow. Excess fluid accumulates, resulting in glaucoma.
How do I know if my pet has Glaucoma?
There are many symptoms of glaucoma that may develop over the course of days but can develop in just a few hours. The eye may develop a whitish/bluish haze in the cornea(the normally clear front portion of the eye.) The eye may begin to look bloodshot. Your pet may exhibit signs of pain in the eye like squinting or avoidance of being handled/petted around the face. The pupil itself may appear dilated. Over time, the eyeball will become enlarged due to the fluid pressure and may be obviously larger than the normal eye. If any of these symptoms appear suddenly, please get your pet to the vet as soon as possible.
How does Glaucoma occur?
Glaucoma can occur genetically or as a result of injury. Glaucoma that results from genetic predisposition is classified as primary glaucoma. Primary refers to the fact that there is no other precipitating disease or injury. Beagles, poodles, cocker spaniels, basset hounds, Siberian huskies, and Samoyeds are just some of the breeds that may be predisposed. Glaucoma that results from an injury to the eye is classified as secondary glaucoma. The initial injury may be a severe scratch or poke to the eye, chronic inflammation, separation of the of the lens of the eye or some cancers of the eye. Pets that develop secondary glaucoma normally do not develop glaucoma in the other eye and if the injury is treated and resolved, the glaucoma can be reversed. In dog breeds predisposed to glaucoma, once glaucoma develops in one eye, the other eye usually develops glaucoma, often within a year. Treatment then becomes lifelong to manage the pressure, as primary glaucoma can be controlled, but not cured.
How is Glaucoma diagnosed?
Our veterinarians perform a physical exam and will talk to you at length to get a complete medical history. Please be sure to explain to the veterinarian what symptoms you noticed , past medical problems if any, both recent and current medications given, and any other relevant information. The veterinarian will test ocular reflexes, which glaucoma may decrease or eliminate altogether. Tonometry is the definitive test for glaucoma. The veterinarian will measure the intraocular pressure with a special instrument called a tonopen. The surface of the eye is numbed with anesthetic drops, then the tonopen is gently touched to the surface of the eye several times. After 3 to 5 readings are taken, they are averaged together to get a final pressure reading.
If glaucoma is confirmed, you have the option of being referred to a veterinary ophthalmologist who is specialized in treating diseases of the eyes. The ophthalmologist will assess any damage within the eye caused by glaucoma by examining the inside of the eye to look at the lens, retina, and optic nerve. Goniometry uses a special lens to assess the area where drainage of aqueous humor occurs. An ophthalmologist can better determine the progression of the disease and assess recovery. Ultrasonography helps to see the inside the eye to look for complications such as blood clots or tumors if the lens is luxated and blocking the view or if the cornea is too cloudy. These tests help to determine if the glaucoma is primary or secondary and the best method of treatment. If referral is not a realistic option for you, the veterinarian will check for secondary causes by testing for tear production, checking for aqueous flare (indication of infection), and staining the eye to look for abrasions or ulceration of the cornea. Treatment with medications will begin immeadiately based on the outcome of these tests.
Longterm Treatment of Glaucoma
Glaucoma may require lifelong treatment. Treatment with combinations of ophthalmic drugs and regular tonometry readings to monitor pressure will be required. For some pets however, medications alone may not be enough to control the building pressure for the longterm. Glaucoma is very painful when the pressure can not be controlled, so pets that have recurrent or uncontrollable glaucoma often need eye surgery for relief of chronic pain.
Whether medication or surgery is used the goals are to treat the cause of the disease when possible, to prevent blindness if possible and to lessen pain. It is important to understand that if medication alone fails to keep the pressure under control, the pain persists even if blindness results. The pain of chronic glaucoma may only be relieved by surgery in which the contents of the eye(evisceration) or the whole eyeball (enucleation) are removed. Unfortunately, blindness is a common complication of glaucoma. If your pet becomes blind as a result of glaucoma, please know that many dogs and cats have a perfectly fine quality of life with vision in only one eye and even do well with total vision loss. Since dogs and cats rely more on other senses, like smell, much more than people do, they often adapt very well.
Sunday Urgent Care Clinic
7 Days a Week
By Appointment Only
Monday thru Friday:
8:00 am to 7:30 pm
Saturday & Sunday:
8:00 am to 4:30 pm
Back Mountain Veterinary Hospital
105 West Center Hill Rd
Dallas, PA 18612