VETERINARIAN
ACTHA Monthly | July 2015 | 38
By Dr. Mary Beth Hamorski VMD
Mixed Animal Veterinarian/Co-Owner Califon Animal Hospital
Califon, New Jersey
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I remember vividly having my yearly eye exam and having to read a laminated piece of paper that stated, "One pair of eyes must last you a lifetime. Take good care of them!" The same is true for your horses' eyes. My staff is trained that several calls are considered priority emergencies; colic, arterial bleeding, a foal stuck in the birth canal and yes, eye issues!!! An eye problem can turn bad in 24 hours if not aggressively treated.
Why is it so important to call you vet right away? First of all horses live in an environment full of fungal elements, bacteria, manure and good stuff to rub on. As we all know, we cannot tell them, “Do not rub your eye!” Animals with laterally positioned orbits have a different field of vision compared to humans. Horses have tremendous peripheral vision but reduced binocular vision (the ability to maintain visual focus on an object with both eyes) and depth perception. And like humans special instruments are needed to fully diagnosis eye injuries.
The most common eye problems are corneal ulcers. In simple terms the cornea is the clear part of your eye encasing all of the contents. It is made up of 4 layers, much like an onion skin. Any insult can rub off a few layers and can be detected by your vet using a special stain. If the stain falls into the defect it will turn green. Another special stain may turn pink if a fungus or virus is present. This condition is known as a corneal ulcer and can be caused by a bacteria, fungus, yeast, virus or immune mediated process. Your vet can assess how deep the ulcer with the use of an instrument called an ophthalmoscope which can also visualize the back parts of the eye including the retina and fundus.
Your vet may also want to take a look at the cells. This is done by applying a topical numbing drop then rubbing the area with a sterile swab or blunted end of a scalpel blade. These cells are then sent to a lab for interpretation (cytology). Your vet may also take an additional swab for a bacterial and/or fungal culture. A bacterial culture may take a few days to be identified whereas a fungal ID may take several weeks, so your cytology sample may guide you earlier to an appropriate treatment plan.
Other issues that are less common are equine recurrent uveitis or moon blindness. Much more research is needed to uncover the way this disease affects the cornea and inner structures which can result in blindness in one or both eyes. Most horses initially appear painful without having a corneal ulcer. Many owners detect a cloudy film over the entire cornea and observe the eyelashes typically pointing downward. Now is a good time to know what your horse looks like under normal circumstances! Certain diseases can lead to uveitis like leptospirosis but many times the initial insult cannot be found. This condition responds to steroids but if you place steroids in an infected eye you may end up with a fungal infection and a non-healing ulcer! NEVER EVER place an eye medication into your horse’s eye without checking with your vet. Doing so may cause the loss of the eye and I have personally seen this happen resulting in an empty eye socket.
Eye Injuries