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

The research conducted at the Western College of Veterinary Medicine (WCVM) studied cases of glaucoma in horses, a condition that was witnessed in 6.5% of the horses. The condition was primarily found connected with manifestations of uveitis and was most prevalent in mid-age to old horses, showing varying clinical signs. Different medical and surgical treatments were applied, however, the visual outcome remained unfavorable as most affected horses either already presented blindness or developed it within weeks.

Context of the Study

• The study was based on equine glaucoma cases reported at the Western College of Veterinary Medicine (WCVM) during 1992 to 1999.
• The research sought to understand the prevalence, associated conditions, manifestation, and treatment outcomes of glaucoma in horses, a condition commonly causing irreversible blindness.

Findings on Prevalence

• Over a 7-year period, the prevalence of equine glaucoma recorded by WCVM’s ophthalmology service was 6.5%.

Associated Conditions

• Most cases of glaucoma were associated with clinical manifestations of another eye disease known as uveitis.
• A single case showed congenital glaucoma, a condition present since birth, and primary glaucoma, resulting not from another disease but an imbalance in eye fluid production, was also diagnosed in one 12-year-old horse.

Clinical Manifestations

• Manifestations included blindness, corneal edema, corneal vascularization, buphthalmia, corneal striae, recurrent ulcerative keratitis, and others less common signs like, optic disc cupping and iris bombé.
• The average age of the affected horse was middle-aged to old (average age = 9.5 years), and no correlations were found with breed or sex.

Diagnosis and Treatment

• The diagnostic confirmation of glaucoma was done by measuring elevated intraocular pressure. However, three cases were normotensive yet showed signs of glaucoma.
• Treatments on affected eyes comprised of a mixture of medical and surgical procedures.

Outcomes of Treatment

• Despite the implemented therapy, the visual prognosis was poor for most of the treated horses.
• Most affected horses were already blind upon presentation or developed blindness within a few weeks, thus indicating the severe and often irreversible nature of equine glaucoma.