Eosinophilic keratoconjunctivitis in seven horses.

The research article focuses on seven cases of eosinophilic keratoconjunctivitis in horses examined at The Ohio State University between 1976 and 1994, investigating the symptoms, findings, and treatment methods used and their outcomes.

Background

• This study centers on eosinophilic keratoconjunctivitis, a specific type of eye inflammation in horses.
• The researchers examined seven reported cases at The Ohio State University over an eighteen-year period, from 1976 to 1994.

Findings

• All seven horses diagnosed with eosinophilic keratoconjunctivitis exhibited moderate-to-severe signs of eye discomfort and inflammation. These signs included blepharospasm, chemosis, and conjunctival hyperemia, all terms that refer to eye muscle contractions, swelling, and abnormal blood vessel dilation, respectively.
• The horses also produced an excessive amount of yellow-to-white, cheese-like eye discharge, stemming from corneal ulcers related to the disease. These ulcers were present in a perilimbal pattern, meaning they occurred along the circular border between the white and colored parts of the horse’s eye, and extended centrally.
• Corneal scrapings examined under a microscope revealed the presence of numerous eosinophils, a type of white blood cell, interspersed with epithelial cells, few mast cells (another type of white blood cell), and neutrophils (a subtype of white blood cell responsible for fighting off bacteria and fungi).
• No microbial organisms were identified in these corneal scrapings, and bacterial and fungal cultures showed negative results for pathogenic organisms.

Treatment and Outcomes

• Eosinophilic keratoconjunctivitis was conclusively diagnosed based on clinical signs and cytological findings. Five of the affected horses completely recovered after local treatment with corticosteroid and triple antibiotic ointments.
• The mean treatment time spanned 64 days, ranging from a 45 to 106-day period.
• Despite this extensive treatment period, the corneal ulcers caused by the disease remained superficial, meaning they did not penetrate the thinner, front part of the horse’s cornea. Additionally, no secondary bacterial or fungal keratitis (corneal infections) developed during this period.
• One horse underwent a superficial keratectomy, a surgical removal of the cornea’s outer layer, and experienced the quickest recovery time at only 14 days post-procedure.