Dogs suffer from a lot of the same problems people do, including eye problems. But until my dog got glaucoma, I hadn’t needed to know about anything beyond foreign objects irritating a dog’s eye or scratching the cornea. That changed three weeks ago, when our shiba inu’s squinty eye stopped responding to the standard antibiotic/steroid topical medication for supposed minor injury. So here’s what we learned.
Yes, dogs can get glaucoma
Dogs can get glaucoma, both primary and secondary (caused by injury or disease). According to PetMD, primary glaucoma is a hereditary disease. PetMD, Petside.com and other sites mention beagles, cocker spaniels, basset hounds, toy and standard poodles, Boston and other terriers, miniature schnauzers, spitz-type dogs( including the Siberian husky, Chow chow, Samoyed and shiba inu), and mixed breeds as being most likely to develop glaucoma. Affected individuals should not be bred but the disease generally doesn't show up until middle age (4 years old or older). In 50 percent of cases, the second eye also develops glaucoma within two years of the first. The other 50% could be lucky and have longer before symptoms spread—or they could, like our dog, have the second eye affected within a month.
A squinty dog should be checked for glaucoma
Glaucoma, an increase in fluid pressure in the eye, happens whenever the production of fluid inside the eyeball happens faster than that fluid can drain. This has nothing to do with tear production (tears are external to the eyeball), except that the painful pressure of glaucoma may make your dog paw at the affected eye, and the irritation from that may cause the eye to shed tears. If your dog squints or rubs at one or both eyes, see a vet immediately. It could be a scratched cornea or irritation from a foreign body under the eyelid—or it could be the first signs of developing glaucoma. Particularly if your vet sees no signs of injury, he or she should check the dog’s eye pressure.
Not gradual like human glaucoma
Canine glaucoma is not like human glaucoma in some very significant ways, even though the same medications are used to treat it. The worst difference: According to Dr. Annora Sheehan Gaerig, DVM, a veterinary ophthalmic resident at Eye Care for Animals in Wheeling, IL, glaucoma in dogs progresses much faster than in humans. At best, medications may slow progress to blindness in an affected eye for weeks to months.
Medication is started immediately to preserve the unaffected eye as well, which can delay onset in the unaffected eye from an average of 8 months untreated to about 2-3 years later. But as Dr. Amy Hom, DVM, of Eye Care for Animals in St. Charles, IL, reminded me, those are averages. You could get lucky and have your dog’s glaucoma well controlled for years—or unlucky and have your dog go blind within a month of the first squinty discomfort.
If the glaucoma is caught very early, a laser technique offers about 75% success in slowing pressure buildup and saving vision for a time—but that also means a 25% chance of failure, leaving your dog with post-op pain and no advantage. A hard decision, that.
You still have to treat the problem after the dog goes blind
The overpressure in the eye can cause pain analogous to a migraine headache, so even after irreversible retinal damage has destroyed the sight in an affected eye, you still need to choose some additional form of treatment to relieve the pressure. This can be as drastic as removing the eye (which has the advantage that no further eye-related problems can crop up) to the minimally invasive injection of gentamicin to inhibit production of the intraocular fluid that is causing the problem (advantage of essentially no recovery time).
Blindness is a relatively minor handicap for dogs
The only good news connected to a diagnosis of canine glaucoma is that, for dogs, losing eyesight is more analogous to losing ability to smell than eyesight for humans. Humans who can’t smell lose an important sense: they can no longer enjoy an important memory cue, they cannot count on being able to smell dangers like smoke or gas leaks, and food loses nearly all taste. But humans organize their lives primarily by sight, with hearing coming a close second. For dogs, scent is primary, with hearing and vision being secondary orientation. Yes, they lose a useful sense, but once they have adjusted and learned to compensate, other people may never guess that your dog is blind if the eyes are intact. I know, I grew up with a dog who went blind at 4. She lived 10 more years and no one knew she was blind until we told them.