The best candidates for cyclosporine implants are those who have not yet suffered extensive damage or vision loss. Ideally, their ERU should be controllable with topical medications, even if the horse has frequent recurrences. Vision should be good between episodes, there should be minimal scarring or cataract formation, and little to no retinal degeneration or loss of function. Any other active systemic illness, such as a high blood titer for leptospirosis (indicating that disease is still active), might also rule a horse out for the surgery.
“In the best case scenario, we would like to install these implants before too much damage has been done by ERU,” said Brooks. “But we don’t always have that luxury. We want to try to save their sight as long as possible.”
With the cyclosporine implants not yet widely available, this is specialized surgery which is not offered on a routine basis across North America, but if your horse has moon blindness, it’s worth seeking out a veterinary ophthalmologist at your nearest university veterinary college. ERU horses need no longer continue to be blinded by the light.