Equine Ailments - A to Z
Periodic opthalmia (moonblindness) - Usually only one eye is affected by this disease. The whole eye undergoes progressive inflammatory change, after a few weeks the eye will seem to recover and then another lapse of the disease will occur. Copious tears are produced and the eyelid becomes inflamed and partially or wholly closed; the pupil constricts and the eye becomes very sensitive to light, it is extremely painful for the horse. Eventually the eyeball shrinks and the lids close over it and the horse is left permanently blind in the affected eye. It is believed to be caused by a virus though it may be caused through bacteria or worm larvae.
Treatment – During an attack the horse should be made as comfortable as possible, kept inside away from direct light. The vet may prescribe antibiotics, corticosteroids and atropine. Treatment will usually only slow the rate of deteriation and the problem tends to reoccur and eventually leads to blindness.
Sometimes the horse is in so much pain that it is kinder to have the eye surgically removed. Horses do seem to manage very well without an eye, I have known cases where the horse has gone on to lead a full life, competing and wining in dressage, show jumping and cross country.