EOSINOPHILIC KERATOCONJUNCTIVITIS IN 7 HORSES

Eosinophilic keratoconjunctivitis was diagnosed in 7 horses at The Ohi o State University between 1976 and 1994. All horses had moderate-to-s evere blepharospasm, chemosis, and conjunctival hyperemia; epiphora; a nd extensive yellow-to-white caseous mucoid discharge. Corneal ulcers associated with this disease were perilimbal and extended centrally. A ll ulcers were covered with a white necrotic plaque firmly attached to the underlying cornea. Other ophthalmic abnormalities were not detect ed. Corneal scrapings examined cytologically contained numerous eosino phils interspersed between epithelial cells, few mast cells, and neutr ophils. Microbial organ isms were not seen. Bacterial and fungal cultu res were negative for ocular pathogens. The initial diagnosis of eosin ophilic keratoconjunctivitis was made on the basis of clinical and cyt ologic findings. In 5 horses, the condition completely resolved after topical treatment with corticosteroid (0.05% dexamethasone) and triple antibiotic ointments. However, the duration of treatment was prolonge d, with a mean treatment time of 64 days (range, 45 to 106 days). All corneal ulcers remained superficial, and despite the prolonged duratio n of treatment, none of the horses developed secondary bacterial or fu ngal keratitis. One horse underwent superficial keratectomy and had th e shortest resolution time (14 days).