Retinal detachment in horses: 40 cases (1998-2005)

OBJECTIVE: To determine clinical features, ophthalmic examination findings, etiology, treatment, and outcome of horses diagnosed with retinal detachment (RD). ANIMALS STUDIED: Forty horses, presented to the North Carolina State University and The Ohio State University Veterinary Teaching Hospitals from 1998 to 2005 that were diagnosed with RD. PROCEDURE(S): Horses with documented RD, confirmed either on ophthalmic examination or by ultrasonography, and with a complete medical record were included. Information retrieved from the medical records included signalment, presenting complaint, duration of clinical signs, ophthalmologic examination findings, diagnostics performed, identified cause of the retinal detachment, treatment given, and outcome. RESULTS: Forty horses (46 eyes) were diagnosed with RD. Mean +/- SD duration of clinical signs of ocular disease was 10.5 +/- 14.7 months. Thirty-four horses presented with unilateral involvement, 6 with bilateral, 14 with partial and 32 with complete RD. Ultrasonography was used to make the diagnosis in 26 eyes, while RD was diagnosed on routine ocular examination in 20 eyes. Bullous RD was the only type of RD observed, although small vitreal traction bands were considered secondary to the underlying inflammation or trauma. RD caused by equine recurrent uveitis (ERU) was diagnosed in 27 of 40 (67.5%) horses. Trauma-induced RD involved 10 of the 40 horses (25%). Presenting problems included known ERU (n = 16), acute or progressive vision loss (n = 9), known ocular trauma (n = 6), cataract (n = 6), and a cloudy cornea (n = 3). No horses regained vision after RD despite therapy. Many eyes were enucleated or eviscerated, or the horses were euthanized. Seven eyes with complete RD were noted to be unchanged and comfortable with medical therapy. CONCLUSIONS: The visual prognosis of RD in horses is grave; however, horses with nontraumatic RD (most commonly ERU) may be able to maintain a comfortable but blind globe with anti-inflammatory medical therapy.