OBJECTIVE: Our objective was to investigate the demographics and prevalence of ocular disease in a large referral population of horses in Ontario over a 10-year period. ANIMALS AND PROCEDURE: A retrospective analysis of medical records for 283 horses evaluated by Board-certified veterinary ophthalmologists at the Ontario Veterinary College (Guelph, Ontario) was conducted. Signalment and ocular disease were recorded. RESULTS: The 3 most common ocular abnormalities identified were uveitis (43.7%, 123 horses), ulcerative keratitis (42.0%, 119 horses), and cataract (25.1%, 71 horses). Uveitis was most often secondary to other ocular disease. Middle-aged horses (5 to 15 y) had a lower proportion of ulcerative keratitis than young horses (0 to 4 y) and older horses (16 to 35 y) ( CONCLUSION AND CLINICAL RELEVANCE: For the first time, the most prevalent ocular diseases and breeds referred for ocular disease are reported for horses in eastern Canada. This study serves as a reference for practitioners and sets a baseline for future studies.