Glaucoma in dogs is a very dangerous eye problem, which frequently leaves a dog blind in the afflicted eye. Basically, glaucoma is a condition in which fluids in the eye do not move or drain properly. This fluid builds up inside the eye, causing a corresponding buildup of pressure within the eyeball. More than half of dogs who develop glaucoma in one eye, even when it’s treated successfully, tend to experience symptoms in the other eye.
In normal eye function, fluid flows slowly between the iris — the colored portion — and the cornea — the transparent bit that covers the iris and pupil. This fluid, called the aqueous humor, is what gives the eyes their rounded appearance. The flow of aqueous humor also regulates and maintains a steady pressure inside the eye. When the aqueous humor is produced faster than it can circulate and drain out, it builds up and creates an enormous amount of pressure inside a dog’s eye. This pressure buildup affects the retina, which processes light, and ultimately, it wears away at the optic nerve itself.
There are two types of glaucoma in dogs, primary and secondary. Primary glaucoma in dogs can be easier to predict and anticipate, since it is largely a hereditary condition. Although primary glaucoma in dogs has been recorded in most every breed of dog, it affects certain dog breeds more than others. Dog breeds prone to glaucoma include Akitas, Alaskan Malamutes, Basset Hounds, Beagles, Bouvier des Flandres, Bullmastiffs, Chow Chows, Dalmatians, Great Danes, Greyhounds, Norwegian Elkhounds, Poodles, Samoyeds, Schnauzers, Shar Peis, Shih Tzus, Siberian Huskies, Cocker Spaniels (American and English), as well as a number of Terriers (Boston, Cairn, Fox, and Jack Russell).
If you are a new parent to one of the dog breeds that are statistically more likely to develop canine glaucoma, it’s important that your regular trips to the veterinarian include an eye exam to keep track of any potential changes in eye health. Secondary canine glaucoma is, however, by far the more common condition. Here, “secondary” means that excess intraocular pressure is caused by a secondary, usually external, source. This can be any kind of trauma or injury to the eye that prevents fluid from draining normally.
The signs of glaucoma in dogs are consistent, regardless of whether the condition is primary or secondary. Symptoms include excessive tear production, blinking, squinting, or a dog pawing repeatedly at his eyes or head, which indicate headache and eye pain. You may notice an eye bulging because of fluid buildup and reddening of the sclera (the whites of the eyes). There may also be cloudiness in that part of the eye covered by the cornea, from the iris inward to the pupil. The unfortunate fact is, that by the time these symptoms become noticeable, a dog may already be experiencing deterioration of the optic nerve and losing sight.
Since secondary glaucoma can be caused by a wide variety of dog eye health issues and develop over time, it’s advisable to take a look into your dog’s eyes from time to time to make certain they appear normal. Any kind of injury or trauma to the eye can prevent free flow and drainage of the aqueous humor. If a dog runs in the woods, goes nosing around in prickly shrubs, or even rubs against a piece of furniture the wrong way, the smallest scrape or wound can be the starting point for canine glaucoma. Early treatment of a minor wound to or around the eyes can prevent a lot of heartache later.
If any of these signs appear in one of your dog’s eyes, immediate action should be taken to prevent vision loss. Your veterinarian will numb the afflicted eye and use a tonometer to gauge the pliability of the eye and determine the amount of pressure within. If glaucoma in dogs is caught early enough to be treatable, medications can be prescribed to lower the fluid pressure in the afflicted eye or to restrict the production of aqueous humor until the intraocular pressure can normalize on its own.
If it can be treated, management becomes key. Managing glaucoma in dogs will require periodic visits to the veterinarian to monitor the pressure in the afflicted eye. Within a few months to two years after the eye is treated, dogs who have had glaucoma in one eye are likely to develop it in the other. Careful observation and monitoring of the treated eye will help prevent recurrence of fluid buildup and ensure that the unafflicted eye remains healthy and viable.
If glaucoma is acute or severe enough, and the veterinarian determines that the condition is irreversible (or that sight loss is inevitable), even with treatment, many long-term cases require the eye to be surgically removed. For dogs in whom glaucoma has developed over time, the total loss of vision from eye removal can be adjusted to, since it is likely their vision in that eye has been deteriorating for some time. Dogs who must lose an eye to glaucoma-related surgery can adapt to the loss, though they may require extra assistance with stairs or other uneven surfaces until they acclimate.
Dogs who are treated for glaucoma, primary or secondary, can still live long and otherwise normal lives afterward.
Have you ever had to deal with glaucoma in dogs? Have you managed the condition following treatment, or did the condition require your dog to part with an eye? Please, share your experiences with glaucoma in dogs in the comments!
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