Advancements in the diagnosis of corneal ulcers, as well their medical and surgical treatment, were among the topics covered by Dennis Brooks, DVM, PhD, Dipl. ACVO, Professor of Ophthalmology at University of Florida College of Veterinary Medicine, during the first AAEP Focus on Ophthalmology meeting, held in Raleigh, N.C., in October.
Brooks said whenever a horse presents for eye pain it should always be examined for possible corneal ulceration. If the veterinarian confirms corneal ulceration through their examination of the eye, it should always be treated aggressively regardless of how minor it might appear.
Veterinarians use fluorescein dye to determine the presence and extent of corneal damage/ulceration in a horse's eye. They might also utilize Rose Bengal dye to determine the disruption of the tear film or the possible presence of fungal contamination, which can be negative to fluorescein dye in the early stages of the injury/ulceration.
Sterile swabs for culture of the affected area of the cornea should be obtained in rapidly progressing or deep ulcerations. Culture of the affected lesion should be followed by "scraping" of the edge of the corneal defect for cytology to determine the presence of either bacteria or fungal hyphae and to allow for more targeted treatment of the lesion.
For either procedure the horse may need to be sedated as well as have anesthetic nerve blocks performed to block motor and sensory input to the eye, as well as a topical anesthetic applied directly to the eye, to allow for examination and treatment. Once the horse has been sedated and the eye has been blocked, the veterinarian uses the blunt edge of a sterile scalpel blade or other instrument to scrape cells from the edge of the lesion/ulcer.
Unfortunately there is no single drug or combination of drug therapy that works for all ulcers in all regions of the country. The reason for this is that the pathogens that affect the eye are different in different regions and climates. For this reason it is important that your horse be treated aggressively with medications found to be useful for pathogens in your particular area. In addition to topical medications horses are also placed on systemic medications, including anti-inflammatories and antibiotics to further assist in treating the injury.
Treating eyes is an extremely time consuming, often frustrating (as most horses are not big fans of having multiple medications put into their eye every 1-2 hours around the clock), and expensive endeavor (some antifungal agents can cost well upwards of $200 for a small tube). However, Brooks reiterated the quicker and more aggressively you treat ocular ulcers the better the likelihood for a successful outcome.
It is also important to realize that often times that the affected eye might appear worse on the first couple days following the initiation of treatment due to the body's response to the death of the pathogens.
Bringing together some of the top researchers, surgeons, and practitioners, the AAEP Focus on Ophthalmology meeting combined lectures on current thought and techniques, goals of future research, and a generous portion of hands-on labs ranging from basic eye exams to microsurgery techniques. The meeting was attended by both American and international practitioners wanting to gain further knowledge and expertise in dealing with issues affecting the equine eye.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.