exams. If they feel an eye needs additional care, surgery or diagnostics, an equine ophthalmologist may need to get involved,” Dr. Gardner, an ACVIM board-certified internal medicine specialist, explains. “There aren’t a lot of equine ophthalmologists around, so if one is not available then sometimes a specialist, such as in internist, can provide more intensive diagnostic evaluation and treatment of equine eyes.” After a general eye exam by your regular vet, Dr. McMul- len, who is an equine ophthalmolo- gist, says if there are any questions, the next step is an ophthalmologist able to perform a secondary ocular exam. “This is the best way to find out if a question- able finding is, or will lead to, a more significant problem. In many instances, early identification and correct inter- pretation can help to determine the long-term influence on a horse’s vision,” he explains. “With time, there are more people interested in equine
but in the future they may be more common and affordable.” Dr. Gardner cautions horse owners should never
put anything in their horses’ eyes without first consult- ing a veterinarian. “If you have something left over from one horse, don’t use it in another horse! Horses’ eyes are extremely sensitive to infection, especially fungus. They could get an infection from another horse, or if you put steroids in a horse’s eye that has a small ulcer, they are very prone to getting a fungal infection, which is then challeng- ing to treat. In horses especially this can be really devastat- ing: instead of a little tube of ointment, you’ll need surgery and eye catheters—and this is not theoretical; it definitely happens.”
Dr. Richard McMullen
ophthalmology and treatment modalities. I think we still have a discrepancy between what an ophthalmologist can do and what a general practitioner can do,” he adds. If eye disease is diagnosed and treated early by your veteri-
narian, he notes, there should be positive change in seven to ten days. The eye might not heal completely, but there should be a positive trend toward healing. If there’s not, he contin- ues, then there’s probably an underlying cause that has gone undetected and a referral to an ophthalmologist is worthwhile. “It doesn’t necessarily have to be a physical referral,” he
adds. “Horse owners can just reach out for help. If we get a disease late in the process, it’s harder to help; all of the chronic changes become more difficult and sometimes impossible to reverse. There’s always a fear of higher costs with referral, but generally an accurate diagnosis leads to a quicker, more effec- tive treatment.”
Treatment Methods Treating eye problems can be time-consuming and expen- sive. Dr. Moding says with a laugh, “If your horse does have an eye problem, it’s a good time to phone a friend for a favor!” She also notes that horses may become resistant to having ointment put in their eye. “Some horses, even if you give them a cookie, they’re not having it. In some cases you can also have a catheter system to make it easier to apply medi- cation, because some horses don’t like to have ointment put in their eye. It’s called a subpalpebral lavage catheter. We actually tape and braid it into their mane, and a little tube comes out right under their eyelid. You inject the medication in a port by the mane and it travels through the tube and comes out under the eyelid.” “There are cyclosporin implants that go under the
conjunctiva and slow-release medication,” she continues. “These implants would allow you to not have to march out to the field three times a day. I don’t know that it saves on cost,
40 March/April 2018
When to Remove an Eye “We actually are removing fewer eyes nowadays,” Dr. McMul- len says. “Sometimes globe removal is the most logical and reasonable treatment option. There are, however, situations where an eye is removed prior to referral to an ophthalmolo- gist because the owner and referring veterinarians are not aware of many of the current treatment options available, and there are misconceptions that additional treatments or costs incurred will far outweigh the benefits. Many horses with extensive eye disease, such as corneal squamous cell carcinoma, have a good prognosis following surgery and adjunctive therapy, despite a large portion of the cornea being affected. In such a situation referral for surgery can lead to the horse keeping his eye and having fairly normal vision, long-term. I think a lot of times people think they have to remove the eye to get disease under control and that’s not always the case.” “There are a couple of deciding factors,” Dr. Gardner says.
“We try hard not to take out an eye that a horse can see out of. If however the eye is blind or has an extremely high chance of going blind in spite of treatment, or treatment is very expensive, painful, or the horse is extremely difficult to treat, then we might consider taking the out the eye(s).” “Removing the eye is a last resort but if the horse is blind
and the eye is painful, it’s about all you can do,” Dr. Moding says. “Horses tend to do well with one eye, though there’s definitely a deficit, so we do everything we can to save the eye. But I’ve had horses completely perforate the eye on barbed wire or have uncontrolled glaucoma, and then there’s no chance.”
She has become adept at enucleation, or eye removal
surgery, while the horse is standing up and under general sedation. She notes the cost for this is typically one-third to half the price of surgery under anesthesia. Horses adapt surprisingly well to vision impairments.
Some one-eyed horses are even able to continue their jump- ing and eventing careers, and a completely blind horse has successfully competed in dressage whose rider who gave extremely accurate cues. Horses with one eye become more comfortable over
time. “By moving their head they can see what they’re moving towards, and they also need to trust their rider,” Dr.
Auburn University
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