Retrospective evaluation of surgical outcomes in canine patients with primary and secondary glaucoma following diode endoscopic cyclophotocoagulation.

Abstract

To evaluate the long-term outcome of endoscopic cyclophotocoagulation (ECP) for the treatment of primary and secondary glaucoma in dogs. Retrospective review of dogs that underwent ECP at two referral centers from 2004 to 2023. Medical records of 389 eyes (301 dogs) following ECP were reviewed. Outcomes evaluated included follow-up time, intraocular pressure (IOP), vision status, additional ECP procedures performed, number of medications, and complications. Patient and surgical variables and their association with IOP control and vision maintenance were evaluated. Median follow-up time was 18 months. IOP remained controlled in 90% and 95% of patients at 1 and 2 years, respectively, following ECP. IOP was controlled long-term (2 years) in cases with primary (88%) and secondary (99%) glaucoma. Post-operative vision was maintained in 63% and 49% of eyes at approximately 1 and 2 years, respectively. Median time to vision loss was 6.5 months. Repeat ECP was required in 15.4% of eyes at a median of 19 days post-operatively. Eyes that underwent more than one ECP surgery had a significantly longer median time to blindness (13.8 months) than those that underwent a single ECP procedure (3.6 months; p = .0003). The median number of anti-glaucoma medications decreased from three pre-operatively to one at 1- and 2-year post-operatively. Complications included corneal ulceration (28%), blinding hypotony (11%), retinal detachment (11%), and hyphema (10%). Endolaser cyclophotocoagulation is an effective surgery for maintaining long-term IOP control and extending vision in canine patients with glaucoma refractory to medical management.