Equine glaucoma: a retrospective study of 13 cases presented at the Western College of Veterinary Medicine from 1992 to 1999.

The prevalence of equine glaucoma seen by the ophthalmology service at the Western College of Veterinary Medicine (WCVM) was 6.5%. The majority of cases (11/13) were associated with clinical manifestations of uveitis. Congenital glaucoma was documented in 1 case, and primary glaucoma was diagnosed in a 12-year-old quarter horse. There were no breed or sex predilections evident. Affected horses were middle-aged to old (average age = 9.5 years, ranging from 2 weeks to 23 years). The clinical manifestations of equine glaucoma included blindness, diffuse corneal edema, corneal vascularization, buphthalmia, corneal striae, recurrent secondary ulcerative keratitis, and less commonly, iris bombé, tapetal hyper-reflectivity, complete pupillary occlusion from posterior synechiae, and optic disc cupping. Elevated intraocular pressure confirmed the diagnosis (n = 10), while 3 cases were normotensive with signs of glaucoma including corneal striae and buphthalmia. Affected eyes were treated medically and/or surgically. Regardless of the therapy instituted, the visual outcome was poor. Most affected eyes were blind at presentation or became blind within a few weeks.