Horse Eye Problems
Tuesdays with Tony
By now you already have it marked on your calendar to attend this month’s meet and greet with yours truly. Of course, if you don’t, here is your friendly reminder that this Thursday, May 2nd, 2019 at 6:30pm I will be hosting the world-famous ophthalmologist, Dr. Dennis Brooks. So when you come, you not only get to meet the world’s most famous cat, me, you also get to meet him and ask him all your burning questions about eyes. And I’m here to prep you with a quick tidbit about all the eye problems your horse may, and likely will, encounter during his lifetime.
Superficial Corneal Ulcers
Probably the most common eye condition my docs see in horses is superficial corneal ulcers. What does that mean, you ask? Well, that means that your horse probably did a silly horse thing like scratch his face in a bush, or roll in dirt and then rub his eye on his leg. When he did that, he caused damage to the epithelium (thin tissue layer) of the cornea leaving the layers below exposed to the elements. Luckily, most horses are giant wimps and will let you know right away that they have hurt their eye. You may notice your horse squinting more, tearing, or even some swelling of the eye lids.
Once you call my docs and they come out, they will perform a full ophthalmologic examination of your horse’s eye. This will likely include sedation as well as nerve blocks to make the eyelid less difficult to open. They will then use an ophthalmoscope to examine the surface of the eye as well as the back of the eye. Then they will stain the surface of the eye with fluorescein stain and that is when you will see it, the dreaded yellow spot on the surface of the eye indicating that there is a defect in the corneal epithelium and thus a superficial corneal ulcer has formed.
Once my docs see this, they will prescribe certain topical medications as well as systemic NSAIDs. That’s where your job begins. You’re going to be very diligent and apply medications twice a day, if not more, depending on what my docs tell you. If you are lucky, the ulcer will be healed within a week and your job will be done. Unfortunately, that is not always the case, and some ulcers just do not heal no matter how diligent owners are. That is where I come in. The docs are going to recommend you bring your horse into me at the clinic where I will oversee the docs placing a subpalpebral lavage system in your horse’s eyelid which will allow for more frequent application of topical medications without having to manipulate your horse’s eyelid. I will also ensure that my staff is administering medications to your horse every 2 hours while he is hospitalized. This is great for me, as I get treats and pets every time someone comes in to treat your horse.
On occasion, even with increased medications and the SPL, ulcers may not heal and my docs will have to deride the cornea. I am a bit of a squeamish cat so I usually find a nice warm place to nap when this happens, but from what I have heard around the clinic, this is when the docs take cotton swabs and try to remove corneal epithelium that is not healing and preventing the ulcer from healing.
If, after debridement the cornea has not healed, my docs will probably call in the experts like Dr. Brooks or Dr. Mangan. Everyone at the clinic always gets so excited when the ophthalmologists are coming, though I have yet to figure out why. When the experts come, they will assess the eye and tweak my doc’s plans. They may perform other diagnostics and adjust your horse’s medications. I even heard that horses may sometimes require contacts. I have perfect 20-20 cat vision so I wouldn’t know what it is like to have contacts. My docs tell me a horse having a contact is not the same as humans, but instead the contact acts as a protective barrier on the cornea to encourage ulcer healing. As you can see thus far, eyes can be a giant pain in my kitty rear-end, so remember, if you notice your horse showing signs of eye problems, call the clinic ASAP and get my docs on the job.
We all live in Florida for a reason, the warmth! There is nothing better than laying on the hood of the doc’s trucks and taking a warm sun bath, ahhhhh I love Florida! Unfortunately, horse eyes do not have the same love for Florida that I do. The heat and humidity here make for an excellent breeding ground of fungi and bacteria, which also means that your horse’s eyes are at an increased risk for developing stromal abscesses. This is when the fungi or bacteria find a tiny little defect in the cornea and work themselves into the deeper layers of the cornea. The defect heals without you even noticing any problems and then a few days later you come out and see that your horse is squinting, has a lot of tearing from his eye and is very, very painful.
You’ll call my docs out and they will perform their usual ophthalmologic examination. Except this time they will not find an ulcer. Instead, they will see a white dot somewhere below the corneal surface. This is the result of the body trying to combat the fungi or bacteria that has gotten into a place it shouldn’t be. Stromal abscesses are even more difficult to treat, and my docs will almost certainly place an SPL and start your horse on multiple medications including anti-fungal medications. You will probably decide that you want to bring your horse in to me for treatment so that you are not having to get up at all hours of the night to treat your horse. Of course, I will always oblige and love to have the company, the more the merrier, right?
Stromal abscesses take what seems like forever to heal and sometimes even require surgical intervention. My docs do not perform corneal surgery; that’s when they call in the experts again. Even after surgery, stromal abscesses take a lot of care and time, but in the end they are rewarding when all your hard work has paid off and you horse’s eye has been saved.
Equine Recurrent Uveitis
Equine Recurrent Uveitis an immune mediated disease. I have diabetes, but that’s not an immune mediated disease, that’s just because I used to be a fat cat. Immune mediated means that the horse’s body is attacking its own cells, in the case of ERU, the horse’s body is attacking its eyes. Eeek!
ERU is a common cause of blindness in horses and is a painful disease. You will notice that your horse’s pupil is very small at all times, even in the dark, they will likely be squinting, and may have tearing. You may also notice that your horse’s eye appears to be smaller. ERU can affect one or both eyes and is most common in Appaloosas but can occur in any breed of horse. If ERU is left untreated, your horse’s retina may become detached or a cataract may form in the lens of the eye.
My docs will assess your horse’s eye and usually will see that his eye is smaller, they may notice that there are blood vessels surrounding the cornea and the eye may be cloudy. They will recommend treatment that will include immunosuppressants topically and sometimes systemically. They will also put your horse on systemic NSAIDs for pain control. Some horses require lifelong treatment and may require surgery to place an implant that releases immunosuppressants slowly over time. The goal with treatment is to decrease the number of times medications are administered to the fewest times possible while maintaining your horse’s comfort.
By now, you’ve listened to me, and you’ve listened to my docs and you know that if you notice any of these signs or symptoms, you will call the clinic or emergency line because, remember, eye problems are always an emergency!
These are by no means the only eye problems that horses have. In fact, I’ve only just begun to scratch the surface of problems. But I have been up for more than 5 minutes now and must nap before I prepare for my next nap. So, if you want to hear more about eyes from the expert, come out to see me on Thursday night. Remember you can always watch the seminar on Facebook live or later on my YouTube channel.
Until next week,
P.S. If you want to know more about equine eyes, make sure you check out the podcast my docs put out. It’s called Straight from the Horse Doctor’s Mouth. The episode on eyes is ah-mazing 😉
Tuesdays with Tony is the official blog of Tony the Clinic Cat at Springhill Equine Veterinary Clinic in Newberry, Florida. If you liked this blog, please subscribe below, and share it with your friends on social media! For more information, please call us at (352) 472-1620, visit our website at SpringhillEquine.com, or follow us on Facebook!