Eye Problems Part 1

Eye Problems Part 1

Tuesdays with Tony

“Granny, what big eyes you have!”

“All the better to see you with, my dear!”

This doesn’t just apply to wolves and Little Red Riding Hood. Typical of prey animals, horses have giant doe eyes that sit toward the side of their heads and protrude out into the environment. Along with nearly wrap-around vision, having wideset eyes makes horses more prone to eye injuries. As you all know, eye injuries are always an emergency, and you should always call your veterinarian at the first sign of an eye problem.

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Given the importance of eyes and the numerous illness and injuries that can affect the eye, this will be a two-part blog. This week we’ll discuss Uveitis and Ulcers, and you’ll have to tune in next week to see what we’ll talk about then. That’s me building antici-purr-tion. And that’s a cat joke.

Uveitis

Equine Recurrent Uveitis, otherwise known as ERU, is a disease of the eye that can affect any horse of any age, breed, or gender. That being said, there are certain breeds that are more prone to ERU, like Appaloosas. Let’s break down each word of Equine Recurrent Uveitis. Equine, that one is simple, equine means horse. Recurrent, means occurring often or repeatedly. Finally, Uveitis, that one is a little more complicated. Uveitis basically means inflammation of the eye. More specifically, it’s inflammation of the layer of the eye that lies between the retina and the sclera and cornea which includes that iris, ciliary body and choroid. So ERU is inflammation of a horse’s eye that occurs frequently.

Signs of ERU are often very subtle. They can range from mild, clear discharge from the eye to thick mucoid discharge. There may also be occasional swelling of the conjunctiva and eyelids. More obvious symptoms can range from cloudiness of the eye to squinting. As you can imagine, with chronic inflammation come other underlying problems. Frequent inflammation results in the development of scar tissue which can affect the lens of the eye leading to cataract development and blindness. Similarly, uveitis can result in decreased drainage of the fluid within the eye which can cause an increase in ocular pressure. As the pressure increases, glaucoma develops and blindness occurs, and you can imagine the headache your poor horse must have. This stuff is painful!

Prevention and treatment of uveitis flare-ups are key. Unfortunately, there is no cure for ERU and long-term prognosis is guarded. Prevention is difficult but keeping your horse in a UV-resistant fly mask is your best tool. Catching symptoms early can help reduce the effects and control the pain. Systemic anti-inflammatories including bute and banamine can help during a flare up. However, topical application medications including steroids such as dexamethasone, topical atropine and/or topical non-steroidal anti-inflammatories including diclofenac reduce inflammation and minimize damage. Surgical implantation of a cyclosporine implant slowly releases the immunosuppressant for up to 3 years and reduces the occurrence and severity of ERU.

As I mentioned earlier, end-stage uveitis can result in cataracts and glaucoma, ultimately causing blindness. It can also result in shrinkage of the eye to the point of complete loss of the eye. Treatment of an end-stage uveitic eye is a salvage procedure and includes injection of medications including the antibiotic gentamicin or the steroid triamcinolone into the globe. The result of such injections kills the eye, causes complete blindness but also reduces the pain associated with ERU. Alternatively, a severely uveitic eye may be a candidate for enucleation where the globe is surgically removed. Either way, the ultimate goal for end-stage uveitis is to alleviate all pain associated with the eye.

Ulcers

Corneal Ulcers are a frequent occurrence in horses. I swear, they must find any bush or tree or shrub and intentionally stick their head directly in it with their eyes wide open. Horses really aren’t the smartest creatures on the planet. The smallest piece of sand or tiny little branch can wreak havoc on horse’s eyes, and a small abrasion on the eye can result in a defect of the cornea and a corneal ulcer. Corneal ulcers can range from superficial to deep and even can risk perforating the eye completely. A perforated eye can be disastrous for both horse and owner.

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Corneal ulcers can present similarly to uveitis. You may notice tearing, swelling, and squinting. If you ever notice any of these signs, it is your cue to call your veterinarian. Do not pass go, do not collect $200, just call your vet. An ulcer that is treated quickly and effectively can heal within days. Left untreated, a corneal ulcer can become a melting ulcer, or worse, can perforate the eye within days. Once diagnosed with an ulcer, your veterinarian will prescribe a very specific treatment regime that can range from 2-3 times a day medications to every 2 hours medications, depending on the severity of the ulcer. Trust me, they do not prescribe every 2 hours medications just for fun. They know exactly how much effort it takes but they also know that if you follow their instructions, it is very likely that the ulcer will heal and your horse will have a functional, seeing eye.

Occasionally, treatment may require the insertion of a subpalpebral lavage. A subpalpebral lavage, or SPL, is a system made up of tubing that is placed through your horse’s upper or lower eyelid and held in place by a footplate that rests inside the eyelid along the conjunctiva. The tubing is then weaved through your horse’s mane and a catheter with an injection cap is secured to the end. This system allows for easy medication administration directly to the eye without having to manipulate the eye itself.  SPLs are reserved for severe cases which require frequent administration of numerous medications.

While corneal ulcers can be simple and resolve quickly, they can also cause major problems and lead to long-term dysfunction of the eye. I cannot stress this enough: if you think your horse has a problem with his eyes, call your veterinarian immediately

Stayed tuned for next week’s Part 2 on eyes.

Until then,

-Tony

P.S. If you can’t wait a week to learn more about eyes, head on over to the Podcast Page and scroll down through the Straight from the Horse Doctor’s Mouth library. There are several episodes on eyes, more than enough to tide you over for a week. There are nearly 100 episodes altogether so far, which is a lot of horse doctor knowledge. That’s nearly as valuable as cat knowledge. Nearly.

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!

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The Seed Heads Are Coming!

The Seed Heads Are Coming!

Tuesdays with Tony

There’s a plague arriving soon. Well, some think it’s a plague, some are grateful, and most of you are in between. I’m talking grass seed heads. Here in North Central Florida, these pop up on a stalk, looking like the letter V waving in the non-existent summer breezes. Seed heads in your area of the country may look different, but they exist all over and summer is their season! My cat self is rather indifferent to the presence or absence of seed heads. However, my Docs can get pretty worked up over these things. This week, let’s talk all things grass seed head. Who knew this could be a blog topic!

The one good thing

This will be short. Seed heads are the grass reseeding itself. This helps your pasture stay full of lush, thick, grass year after year without having to reseed it yourself. This is a good thing. I mean it’s a really, really good thing to do, so don’t think I’m discounting the goodness of seed heads. We are now done with good things.

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Eyeballs

Why oh why must horses have big, beautiful bug eyes on the side of their heads??? I am a wise cat. I know the real answer is so that they can see predators coming at them across the savannah for miles and miles. The problem is those eyes are right at seed head level. Those seed heads love to drop right in there and stay for a while. Not being graced with fingers, your horse will have a very hard time getting the seed head out of their eye. This leads to a couple less than ideal options. 

The first involves your horse rubbing their eye on anything and everything they can find until they rub that seed head out, and likely develop an ulcer. As their human, you will usually notice some swelling and tearing the next time you see your horse. You may also notice a small white spot, generally around the edge of the cornea somewhere. This should be treated as an emergency, and you need to call my Docs immediately. It doesn’t necessarily mean they are going to come out, but they do want to talk to you about any and all eye things as soon as you find them! These ulcers are usually small, and respond readily to a few days of ointment and anti-inflammatories. 

The second scenario is by far my favorite. That seed head doesn’t get dislodged by your horse’s attempts. Instead, it gets stuck to the cornea, and the eye tries to dislodge it by growing tissue under it. At some point in this process you will notice what appears to be a brown bump in your horse’s eye, again usually near the edge. It’s amazing to me that there is often no other sign. Your horse may not be squinting, or have a runny eye. I’ll be honest, this is one of my favorite things to supervise here at the clinic. Why? Because it’s pretty easy and fun to fix. My Docs will put some numbing drops in the eye, give the horse a little sedation so they don’t move, and then pop the offending seed head off with a needle. There’s usually a tiny, tiny ulcer underneath the seed head, so the Docs will send you home with a few days of eye ointment, but that’s it. Off they go to heal perfectly. 

What to do? Make sure your horse goes out with a fly mask! While keeping flies and gnats away from their eyes and ears, it will also keep other unwanted visitors out, like grass seeds. Mowing is also an option, but we’ll talk more about that in a minute.

So, so delicious

Moving on to the next problem with seed heads: calories. I’m going to talk mostly about bahia grass since that’s what we have here in Florida, but it’s not that different around the world. When those seed heads start popping up, they bring a whole lot of calories to the party. Ever seen your horse out in the pasture not even bothering to take their nose to the ground? They walk along eating only the tall seed heads. That is weight gain taking place in front of your very eyes. 

As a, umm- larger- member of the domestic cat family, I get it. Delicious food is delicious food and it’s awfully hard to say no to good eats! Those seed heads aren’t just full of calories, though. They’re also full of sugar. I’m a fully-fledged member of the diabetic cat club, so I know this is bad. I also know horses don’t get diabetes, but sugar is still bad. That’s because all those sugars cause the release of something called IGF (insulin-like growth factor), and that messes up a lot of things in the body. 

There are many strategies to reduce those seed heads. Mowing is a fun one. Keeping the seed heads mowed down is a great way to prevent them from going directly into your horse’s belly. It is recommended to let the grass fully go to seed at least once yearly to let it reseed itself. 

Grazing muzzles are another great way to limit the seed heads that go in your pony. My final recommendation is one I avoid at all costs: exercise. As little as 15 minutes three times weekly can prevent many of the side effects of weight gain. Evaluating your lifestyle will help you choose the option or options that work best.

Grass is wonderful. Horses were literally designed to eat it. Like all things horse, they can take something good for them and turn it into something disastrous. Keep an eye on those eyes, and watch that weight for a happy, healthy summer co-existing with seed heads.

Until next week,

~Tony

P.S. Looking for more great horse knowledge? In addition to the hundreds of blog posts filled with my cat wisdom, we also have a fantastic free podcast that will change your life. You can find it over on the Podcast Page of my website. We also have books and videos that the humans have worked hard to share with you, under my supervision, of course. You’re welcome. You can thank me with a chin scratch next time you come by the Clinic.

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!

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