The condition known as “dry eye” can be incredibly frustrating for pet owners and veterinarians. It is the rebel disease that responds to treatment sometimes, not others, for no apparent reason. The symptoms don’t really make sense. The whole package is odd. So, time to explain it!
The medical term for dry eye is KCS – KeratoConjunctivitis Sicca. “Kerato” means cornea, or outer film of the eye. Conjunctiva is the pink membrane lining the inside of the eye, that you typically don’t see without having to pull on an eyelid. And you probably know that “-itis” means inflamed, or angry. “Sicca” is Latin for “dry.” So the whole term translates to an inflamed and dry cornea and conjunctiva. That pretty much describes it!
KCS refers to inadequate tear production. It could be ZERO tears, or it could be some tears, but not enough to maintain eye health. So you might think that if a dog had KCS, there would be nothing coming out of his eye, right? Well, KCS has to be different. Because the eye cannot produce (sufficient) tears, the body gets creative and says “if I don’t have tears, I’ll make what I can, which is this green mucousy stuff. That’s a great idea.” So a dog with KCS typically presents with bloodshot, irritated eyes, and varying levels of thick green mucous. Hey, I never said all the body’s ideas were winners!
When we vets see that, we immediately suspect Dry Eye, particularly if your dog is a certain breed that is prone to it. In my experience, I see this disease the most in Westie’s, Cocker spaniels, shih tzus, and mini Schnauzers. That’s not to say other breeds can’t get it – any dog can! In fact, dry eye is a known side effect of some medications, like sulfur-containing antibiotics. And some dogs can have one normal eye, and one dry eye!
Good news – the test for KCS is quick, simple, and affordable. Bad news – the treatment is none of those things! Let’s talk about the test, which is so low tech, I find it oddly charming. It’s sometimes referred to as a Schirmer tear test. It involves a strip of paper with a band of ink on one end. The round end is placed between the dog’s lower lid and eyeball, so that part feels a little weird. The strip is held in place for 1 minute, and a normal eye will produce tears that move the ink down the strip. Yes, a minute can feel like a very long time! And we have to do one for each eye!
Dogs with KCS might not have tears to even touch the ink, since the ink line starts at about the 5 mark. I have many patients who register a zero. Others move the strip to a 7, or a 12. How do we know the eye is dry? Typically anything less than 10 is diagnostic for KCS. Strips reading 15 or less are suspect, maybe in the early stages? To be honest, in a healthy eye, I usually get to the 20 mark when only 30 seconds have passed, I’ll sometimes stop early if the dog is getting sick of me. Consider that test passed!
So your dog has been diagnosed with KCS, now what? I wish I could tell you the treatment is easy and works great. But I was taught it’s not nice to lie.
The current theory is most dry eye is caused by the body’s own immune system attacking the tear glands. Treatment therefore focuses on calming down, or suppressing, the immune system, known as “immunosuppressant” therapy. We may have to use eye drops with antibiotics to treat any damage to the cornea as well. Long term, the hope is to give eye drops that suppress the immune systems attack and restore tear production.
Well, anyone with any kind of auto-immune disease will tell you, the immune system isn’t the best about following directions. There are two main therapies we use to treat dry eye, both in the form of eye drops or ointments: cyclosporine and/or tacrolimus. Of these, the only commercially available eye ointment is Optimmune, which contains cyclosporine and retails for $50-$60 for a painfully tiny tube. To boot, many ophthalmology specialists feel the concentration of cyclosporine in Optimmune is not enough. We vets often end up having eye medications compounded to have a higher concentration of cyclosporine, and might include tacrolimus. These medications are not cheap as well, and fewer and fewer pharmacies are compounding eye medications due to various state regulations.
I have some dogs respond to this combination, and others who do not respond to anything. After spending hundreds of dollars on eye medications, putting them into the dog’s eyes twice a day for months, it really sucks to see the tear test stay at something sad like a 4. If it does work, and your dog responds, then you get to medicate your dog’s eyes twice a day for the rest of his life, and you’re the lucky one, whose dog lives pain free and gets to see. This is a lifelong condition, and the drops are managing it, not curing the disease. If you are lucky enough to have your dog respond well to these treatments, please do not stop the meds. Ever.
For dogs who don’t respond to treatment, there is a Plan B in the form of a surgical procedure, usually performed by specialists, called a parotid duct transposition. It sounds radical, but it often works! Basically, the surgeon takes the salivary duct that goes from the gland in the cheek to the mouth, and re-routes it to the eye. Yep, your dog’s eye is now lubricated by spit. This works well in some dogs. In other dogs, it’s too much liquid, and now we deal with excessive tearing and the dermatitis/skin infections that can result. So it isn’t a perfect solution, and dogs who have some tear production, like a 6 on the test, are traditionally not candidates, since the saliva combined with the tiny bit of tears they have will be too much, like stopping one battle just to start another.
I personally have a dog who responded to nothing, but her KCS was brought about by a brain disease, not the typically auto-immune cause like most cases are. She also does not produce enough saliva, so the parotid duct transposition surgery was not an option. So what do I do? It sucks, but you’ve probably guessed that I’m a crazy dedicated dog owner, so this won’t be a shock.
My little girl gets her eyes lubed every hour. When I have to see clients, she gets picked up by her grandparents, who are retired, and can take over the lubing. Overnight she doesn’t get lubed (I do have to sleep) but I have a combo I load her up with before bed, and we lube her first thing in the morning. We’ve been doing this for two years, and our lubing is helping, but not sufficient. She’s still getting the damage to her cornea. What happens in these dogs who do not respond to treatment?
Eventually, they lose their vision. It sucks. The cornea, or outer layer of the eyeball, darkens from all the inflammation. It’s like looking through glasses that are covered in paint – there might be a chip in the paint to let some light or shadows in, but that’s it. This pigmentation happens gradually, so many dogs do learn to adjust to the gradual decrease in vision. My dog jumps in and out of the car, climbs the stairs to our bed, and keeps the neighbor dogs in line. Dry eye is also a painful condition. Mercifully, my dog cannot feel her eyes or face (again, from that brain disease) so she is not in any pain from her rediculously dry eyes and mouth. Most dogs aren’t so…lucky, if you call it that?
If your dog does not respond to traditional treatments, lube lube lube those eyes! My favorite product is OptixCare. No, they are not paying me to say this, but I have found that is works epically better than any artificial tears. Liquid drops just run off and are gone in a minute, don’t wast your time. Mineral oil or petrolatum based eye lubricant/artificial tears seems to just sit on the eye and not really soak in. The OptixCare is a gel that both soaks into the eye, to help all those dry parts, and sticks around a while.
If your dog is diagnosed with dry eye, just know that treatment is definitely worth a try, but keep an open mind. And accept my condolences – it’s a crappy disease.