Clinical findings associated with blunt ocular trauma in horses: a retrospective analysis

Objective Identify ocular findings associated with blunt ocular trauma to aid in differentiation from other equine ocular diseases. Study design Retrospective case-control study. Methods Medical records of horses at the Equine Clinic Munich-Riem, Munich, Germany and Auburn University, College of Veterinary Medicine were reviewed. Age, sex, breed, laterality, and clinical findings on ophthalmic examination, as well as an observed (confirmed) or unobserved (suspected) history of trauma, were recorded. Statistical analysis was performed to identify any correlation between clinical signs and blunt ocular trauma. Fifty-nine clinical signs were evaluated, and their association with blunt ocular trauma and non-traumatic uveitis was determined. The frequency of clinical signs associated with non-traumatic uveitis was also reported. Results Fifty-five eyes affected with blunt trauma were included. The comparison group consisted of 233 eyes (168 horses) diagnosed with non-traumatic uveitis. The most frequent ocular findings after BOT included cataract (36/55, 65.5%), corneal edema (26/55, 47.2%), decreased intraocular pressure (23/55, 41.8%), aqueous flare (19/55, 34.5%), lens subluxation, luxation, or lens loss (18/55, 32.7%), fibrin in the anterior chamber (18/55, 32.7%), hyphema (16/55, 29.1%), peripapillary depigmentation ("butterfly lesion") (16/55, 29.1%), conjunctival hyperemia (16/55, 29.1%), corneal fibrosis (15/55, 27.3%), corpora nigra avulsion (14/55, 25.5%), blepharospasm (13/55, 23.6%), and iridodialysis (11/55, 20.0%). Conclusions The characteristic pattern of ocular signs associated with blunt ocular trauma may assist in differentiation from other types of uveitis and may improve interpretation of ocular lesions identified during pre-purchase examinations. This study also represents the first peer-reviewed documented and photographed cases of iridodialysis in the horse.