Eyelid Issues Discussed at Equine Ophthalmology Meeting

From lacerations to cancer, issues commonly affecting the equine eyelid were among the topics tackled by Brian Gilger, DVM, MS, Dipl. ACVO, chief of the Ophthalmology Service at North Carolina State University's College of Veterinary Medicine, during the first AAEP Focus on Ophthalmology meeting, held in Raleigh, N.C., earlier this month.

With the possible exception of entropion (inward folding of the eyelids) in neonatal foals, congenital defects--those the animal is born with--of the eyelid are considered rare when compared to acquired defects such as lacerations.

As eyelid lacerations are a common issue nearly every equine practitioner deals with on a relatively frequent basis, Gilger discussed techniques for successful surgical repair in detail. He also covered local and systemic anesthetic techniques for successful surgical repair in detail during both lecture and hands-on labs.

Masses and tumors, such as squamous cell carcinoma, commonly affect the eyelids and ocular region of the horse. Gilger emphasized the importance of your veterinarian's diagnostic evaluation of the tumor prior to considering proper treatment options.

Tumors such as sarcoids should only be biopsied if treatment is going to be initiated at the same time, as aggravating the sarcoid can increase their aggressive nature, whereas tumors thought to possibly be squamous cell carcinoma require biopsy and histopath evaluation for proper diagnosis.

Squamous cell carcinoma is a relatively common tumor found in lighter faced horses or those with widespread white coloration on their faces, such as Paints, Appaloosas, and Belgians, although it's not limited to these breeds. After proper diagnosis and surgical removal (depending on tumor location) of a squamous cell carcinoma, there are a number of adjunctive therapy options now available that were not an option even as recently as five years ago.

Adjunctive therapy should be considered in order to decrease the likelihood of recurrence rates, as squamous cell carcinoma is an aggressive cancer that with just surgical removal alone has a relatively high rate of recurrence. Some adjunctive therapies available today include:

  • Chemotherapeutic agents such as cisplatin and carboplatin (both of which involve several injections over a period of time), depending on the size of the tumor;
  • Immunotherapy with Bacille Calmette-Gu�rin, a vaccine against Tuberculosis;
  • Cryotherapy (freezing);
  • Hyperthermia (high temperatures);
  • CO2 laser ablation;
  • Gamma radiation (requires isolation protocol due to radiation as well as multiple treatments under general anesthesia);
  • Photodynamic therapy (injecting a cancerous lesion with visudyne and applying a special type of laser to the injected lesion resulting in tissue necrosis (death). Availability of this treatment is limited.);
  • Brachytherapy, the implantation of iridium beads into the tumor (requires about one week of isolation).

The location and extent of tumor involvement are important in helping your veterinarian determine which treatment option is right for your horse. In addition, different veterinary clinics and universities have access to different treatment options, and not all options are available in all areas.

Topical agents might be useful in treating some smaller sarcoids on other areas of the body; however, their use in and around the eye is strongly discouraged due to the delicate nature of the eye. In all cases early and aggressive therapy is recommended for best long-term outcome.

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.

About the Author

Kristen Slater, DVM

Kristen Slater, DVM, practices with Kasper & Rigby Veterinary Associates in Magnolia, Texas. Her practice interests include preventive medicine, reproduction, sports rehabilitation, and conditioning.

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