Normal equine ocular anatomy and eye examination

When compared with small domestic animals, the horse has unique ocular characteristics (complete bony orbit, well-developed eyelid muscles, a nasal and temporal gray limbal line, granulae iridica, paurangiotic fundus). Knowledge of normal equine ocular anatomy is essential for ocular lesion interpretation. It is important to obtain a full history and general examination before sedation, nerve blocks, or other diagnostic ophthalmic tests are performed. All ocular examinations should include a systematic evaluation of both the anterior and posterior segments. Selection of other diagnostic tests depends on information obtained from the history, general inspection, and ophthalmic examination. The appropriate order of performing various special diagnostic tests must be considered before beginning the examination. If a diagnosis is elusive, referral to an ophthalmologist for further diagnostics should be considered.