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Glaucoma signs & symptoms · Glaucoma diagnosis · Glaucoma treatment · Glaucoma related articles
Glaucoma Medical terms: intraocular, tonometer, uveitis, intraocular pressure (IOP), primary Glaucoma, secondary Glaucoma, corneal edema, tearing (epiphora), squinting (blepharospasm), enlarged eyeball (buphthalmos)
Glaucoma in dogs and cats is increased pressure in the eye. The eye is approximately round, like an egg, but rather than having a hard shell like an egg, the eye has a soft flexible outer covering. The flexible eye would collapse except that it is kept expanded by fluid. The fluid is made within the eye at a steady rate and flows out of the eye through a canal at a steady rate. If too much intraocular fluid is made, or if the fluid cannot flow out through the canal, the pressure builds within the eye causing Glaucoma.
What is normal eyeball pressure?
Normal pressure for dogs is approximately 25 mm Hg.
Normal pressure for cats is approximately 30 mm Hg.
Eyeball pressure is low compared with blood pressure. For example, the circulating blood always has a pressure about 80 mm Hg; and in dogs and cats, the blood pressure rises to 140 or 170 mm Hg when the heart contracts.
Eyeball pressure is measured with a tonometer, just as it is measured for humans.
| Eyeball pressure in health and disease in dogs
There may be small differences in pressure from one eye to the other, from one day to another, from one hour to another.
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Normal intraocular pressure (IOP) |
15-25mmHg |
Glaucoma |
25-30mmHg |
Anterior uveitis (inflammation) |
10-15mmHg |
Anterior uveitis & secondary Glaucoma |
10-30mmHg |
Two forms of Glaucoma in Dogs and Cats: Primary Glaucoma and Secondary Glaucoma
Primary Glaucoma in Dogs and CatsPrimary Glaucoma is caused by a problem either with fluid flow within the eye or with flow out through the eye canal. Most pets with primary Glaucoma have too narrow an angle for the fluid to flow easily out of the eye. With primary human Glaucoma, the opposite occurs: the outflow angle is wide.
Secondary Glaucoma in Dogs and Cats
Secondary Glaucoma is caused by a disease that affects the eye so that the eye responds by making too much fluid or by developing a problem with fluid outflow. For example, if your pet has a systemic fungal infection (toxoplasmosis, histoplasmosis, blastomycosis or cryptococcosis) the infection affects the eye, causing Glaucoma. If your pet was hit by a car and the lens within the eye was shaken loose, the lens can block fluid flow and create Glaucoma. With secondary Glaucoma, it is as important to treat the underlying cause as it is to treat the Glaucoma itself.
What causes most cases of Glaucoma in Dogs and Cats?
Your pet is twice as likely to develop secondary Glaucoma—have another health problem that causes the pressure within the eye to increase—than to develop primary Glaucoma.
Why is Glaucoma in Dogs and Cats bad?
Glaucoma can be so painful that humans say it is a 12 on a scale of 1-10. Pain is caused by sudden changes in intraocular pressure or acute-onset Glaucoma. Chronic Glaucoma that develops slowly over time may not be painful.
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Glaucoma is also bad because it leads to blindness. About 40% of dogs with Glaucoma will be blind within a year regardless of Glaucoma treatment. Although Glaucoma can begin in one eye, 50% of pets with Glaucoma develop the disease in the other eye unless they receive Glaucoma treatment.
Who Gets Glaucoma?
Cats seldom develop Glaucoma, but many dog breeds are predisposed to Glaucoma and should have their eyes checked twice a year: Akita, Basset Hound, Beagle, Chihuahua, Chow Chow, Cocker Spaniel, Dachshund, Fox Terrier, Maltese, Norwegian Elkhound, Poodle, Siberian Husky, Welsh Springer Spaniel.
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The articles here were answered by a variety of pharmacists and veterinarians
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Increased tearsSquinting Dilated pupil Avoids light Cornea becomes cloudy Congested vessels on the eyeball Blindness |
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Glaucoma is usually due to a health problem that begins outside the eye, such as an infectionGlaucoma can be very painfulGlaucoma causes blindness |
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AkitaBasset HoundBeagleChihuahuaChow ChowCocker SpanielDachshundFox TerrierMalteseNorwegian ElkhoundPoodleSiberian HuskyWelsh Springer Spaniel |
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| Miotic: |
| Carbonic Anhydrase Inhibitor (CAI) diuretic: |
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Daranide (dichlorphenamide)Neptazane (methazolamide)DorzolamideDiamox (acetazolamide) |
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MannitolGlycerine or glycerol |
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| Cholinesterase inhibitor: |
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