Glaucoma, a condition in which the fluid within in the eye doesn’t drain properly, leads to painful pressure within the eye and can cause blindness within hours without treatment, according to veterinary ophthalmologists Paul Scherlie and Susan Kirschner. Symptoms in pets usually include signs of eye pain, such as rubbing the eye or exposure of the usually hidden third eyelid. Treatment varies and may not always be able to save the dog’s vision. The Oregonian (Portland)
One night in November of 2012, Silverton residents Shelly Brown and longtime partner Jim Sears noticed their German shorthaired pointer, Greta, acting strangely.
Greta was accustomed to staying in her kennel at night, but on this particular evening she kept scratching repeatedly to get out, which was very unlike her.
“She was acting really disoriented and confused, like she didn’t know where she was,” Brown says.
Then Brown noticed that a membrane in the inner corner of Greta’s eye, known as the “third eyelid,” was extended over her eyeball.
Brown and Sears took Greta to Dr. Paul Scherlie, a board-certified veterinary ophthalmologist at VCA Northwest Veterinary Specialists in Clackamas, who treated Greta for glaucoma.
What is glaucoma?
Fluid inside the eye, called the aqueous humor, typically flows through the pupil and drains through a sieve-like network located where the cornea and iris meet. In a healthy eye, the fluid is produced and drains at the same rate, creating a stable pressure.
Glaucoma occurs when the fluid cannot drain properly, causing pressure to build up and damaging the sensitive optic nerve.
In humans, glaucoma is a slow, progressive condition that can be caught with regular screenings. January happens to be National Glaucoma Awareness Month, established by a group of eye health organizations to promote more awareness of the disease.
For canines, the condition can come on suddenly and cause blindness within hours.
The rapid pressure change is extremely painful, resembling an intense sinus pressure or throbbing pain, says Dr. Susan Kirschner, a board-certified veterinary ophthalmologist at Animal Eye Doctor in Beaverton.
There aren’t many ways to screen for or prevent the disease in dogs.
Some are more genetically prone to the condition, including American cocker spaniels, Basset hounds, Chow Chows and Siberian huskies. Locally, Scherlie has also seen it in Labradors.
The Orthopedic Foundation for Animals offers a database of animals certified to be free of any signs of ophthalmic disease that might be genetic.
Secondary glaucoma can be caused by disease or trauma, such as cancer in the eye or inflammation due to uveitis or cataracts.
Cats typically get this kind of glaucoma, usually a result of uveitis.
Symptoms of glaucoma
The most common sign that something is wrong with your dog’s eye is what’s called an elevated third eyelid.
“It almost looks like the eye is rolling up and out,” Kirschner says. “It’s not; it’s an optical illusion, but it’s almost always a sign of pain in the eye.”
The dog’s third eyelid, also known as the nictitating membrane, is a thin piece of tissue that acts as “windshield wiper” across the cornea. It’s usually not visible, but when the eye is irritated from glaucoma or a corneal ulcer, it may become elevated and cover the eye.
This is likely what Brown saw when she noticed something was wrong with Greta.
Dogs may also squint or paw at their eye, or the eyeball may become enlarged and bulge forward.
If Fido gets glaucoma in one eye, it’s only a matter of time before it develops in the other eye.
There is an eye drop that can help delay onset in the healthy eye for up to two years, but your pet will develop glaucoma eventually.
There are lots of treatment options, although Scherlie’s preferred method is simply to remove the eye and stitch the skin shut.
“The benefit to that is immediate pain relief, the stitches are out in seven to 10 days, and there’s no eye to have any future problems,” he says.
For older dogs like Greta, who aren’t good candidates for surgery, there’s the option of injecting an antibiotic into the eye. This procedure kills off the cells producing excess fluid.
Another technique is removing the eye and putting in a silicone implant to keep the eye’s shape, but the dog can still contract other diseases that affect the surface of the eye.
Helping pets adjust
Dogs that have lost most or all of their vision adjust pretty quickly, but there are some adjustments you can make at home that can help.
Stairs, decks and swimming pools pose the biggest threats for dogs that have recently lost their vision.
One thing you can do is put duct tape at the edge of a ledge, such as the bottom stair.
“It can be helpful to have some kind of sensory clue to let them know they reached the edge,” Kirschner says, “so when the dog touches that, it knows there’s a transition.”
Hillsboro resident Heather Blackwell’s Chihuahua, Teddy Bear, had his left eye removed at the Bonnie L. Hays Small Animal Shelter because of glaucoma.
Blackwell has done a few things to help him adjust, such as leaving a nightlight on to make sure he doesn’t tumble down the stairs at night.
“He’s very athletic, but his depth perception is not so great,” she says.
When he approaches the sliding glass door to go outside, Blackwell puts a sticker on the glass when it’s closed so he doesn’t run into it.
Like many blind dogs, Teddy Bear doesn’t seem to notice that he’s missing an eye.
He’s very friendly – Blackwell says he “doesn’t know a stranger” – and since people are often curious about him, he’s become sort of an advocate for blind dogs.
“He’s just a little clown,” Blackwell says. “You wouldn’t know anything is wrong with him.”
Tips Box: How to help a blind pet adjust
- Don’t treat your pet differently once it’s lost vision
- Make sure to seal off decks, banisters, swimming pools or anything else a pet can slide through or fall down.
- Don’t let your dog get bored. Blind dogs still want to have fun, and they no longer have the option of watching “dog TV” by gazing out the window at squirrels and passersby.
- Dogs can memorize the layout of your home, yard and daily walk, but make sure to take them on the same route every day so they can become confident.
- For walks, try passing a thin leash through a short length of PVC pipe. This creates a stiff leash that can help you keep your pet from running into trees or lampposts.
- Don’t hesitate to use more verbal cues. Dogs can learn up to 200 or 300 words, so you can use language to help them navigate where to step.
–Sources: Dr. Susan Kirschner; Dr. Paul Scherlie
Cataracts occur when the lens becomes cloudy and the pupil appears white or gray. They can be caused by aging, as well as trauma or diseases like diabetes.
When severe, cataracts can generate inflammation that can lead to glaucoma. About 80 percent of untreated cataracts develop glaucoma, retinal detachment or luxated lens. These conditions usually only occur as a result of untreated cataract-associated inflammation.
Cataracts can be removed with surgery; about 90 percent of dogs that undergo cataract surgery can return to good vision.
Owners may notice gradual signs that their pet has cataracts, such as a dog having trouble seeing its ball, says Dr. Susan Kirschner, a board-certified veterinary ophthalmologist at Animal Eye Doctor in Beaverton.
Elizabeth Olson of Rabbit Advocates discovered that her bunny, Amelia, had cataracts after noticing the animal’s eyes looked more pearly pink as opposed to their normal red color.
Olson and her husband are trying to modify Amelia’s so she doesn’t bump into things as often, and devise ways to keep her busy, such as building cardboard tunnels and putting treats at the end.
“So far, it has probably been more difficult for us to watch then for her to experience,” she says.