Use of Transcorneal Iris Photocoagulation to Facilitate Sector Iridectomy of Pigmented Iridal Tumors: A Case Series of Five Eyes (Three Dogs and One Cat)-Clinical Findings, Surgical Technique, Complications, and Outcome.

Objective: To describe the use of transcorneal iris photocoagulation (TCIP) to improve intraocular visualization of intended incision lines, reduce hemorrhage, and facilitate excision of pigmented iridal tumors in four canine eyes and one feline eye.

Materials and methods: A Rhodesian Ridgeback (treated bilaterally), a German Shepherd, a Labrador Retriever, and a Scottish Fold underwent sector iridectomy due to rapidly growing, pigmented, raised, iridal tumors affecting 1/4-1/3 of the iris circumference (3- to 4-clock hours). A diode laser was used to delineate the intended sector iridectomy incision lines, approximately 1-2 mm away from the grossly visible tumor margins, with the aim of improving visualization to achieve tumor-free margins and reduce tissue handling/trauma.

Results: All iridal tumors were removed en bloc with tumor-free margins on histopathology. The most common histologic diagnosis was iris melanocytoma (3/5 eyes). The most common intra- and postoperative complications included hyphema and fibrin clot formation (5/5), posterior synechia formation of iris wound margins (5/5 eyes), and photophobia (3/5 eyes). Two eyes required intracameral tissue plasminogen activator (tPA) injections within 2 weeks of surgery. The follow-up period for all operated eyes ranged from 5 to 14 months. Vision was retained in all eyes, with no grossly apparent tumor regrowth within the follow-up times included for each case in the present series.

Conclusions: The use of TCIP to delineate intended incision lines improved intraocular visualization of sector iridectomy surgical margins in this case series. While hyphema and fibrin clot formation still occurred, they were successfully managed.