Clinical appearances, healing patterns, risk factors, and outcomes of horses with fungal keratitis: 53 cases (1978-1996)

Objective: To compare initial clinical appearances, healing mechanisms, risk factors, and outcomes of horses with fungal keratitis.
Design: Retrospective analysis.
Animals: 52 horses (53 eyes) with fungal keratitis.
Procedure: Medical records and clinical photographs of eyes were reviewed. Keratomycoses were categorized on the basis of clinical appearance at initial examination and pattern of healing.
Results: Five distinct forms of mycotic keratitis were recognized. Of 53 affected eyes, 34 (64%) retained sight and had varying degrees of corneal scarring after treatment, 6 (11%) had a cosmetic appearance but were blind, and 13 (25%) were enucleated. Bacterial-like ulcers were the most frequent type and the most difficult for predicting outcome. Eyes affected by superficial fungal keratitis were likely to be chronically infected and to require debridement and extended treatment but usually healed with minimal scarring. Keratomycosis with a surrounding furrow resulted in a grave prognosis. Aspergillus organisms were isolated from 9 of 10 such eyes. Cake-frosting material was a positive prognostic sign. Fungal corneal stromal abscesses tended to be caused by yeast.
Clinical Implications: This information will aid practitioners in recognizing various forms of fungal keratitis and guide them when making therapeutic decisions and prognoses for affected horses.