The use of semiconductor diode laser for deflation and coagulation of anterior uveal cysts in dogs, cats and horses: a report of 20 cases

OBJECTIVE: To describe semiconductor diode laser use for anterior uveal cyst deflation and coagulation in dogs, horses and cats. ANIMALS STUDIED: The presenting clinical signs, surgical technique and postoperative results for four dogs, nine horses and seven cats with anterior uveal cysts treated with diode laser are described. Treated cysts were of sufficient size and/or number to potentially impair vision, damage the corneal endothelium, or increase intraocular pressure (IOP). One dog with free-floating cysts exhibited 'fly biting' behavior. Cysts were suspected of causing shying on the affected side and/or head-shaking behavior in seven horses. Cysts were free floating within the anterior chamber in dogs, occurred in the corpora nigrum in horses and were attached to the posterior iris surface in cats. In cats, shallowing of the anterior chamber and dyscoria were observed. In all cats prior to cyst deflation, IOP increased after pharmacologic pupil dilation. Cats were more likely than dogs and horses to have bilateral and multiple cysts. PROCEDURE: Two dogs and all horses were treated without general anesthesia and two dogs and all cats were treated under general anesthesia. Diode laser was used to perforate, deflate and coagulate the cysts. RESULTS: Postoperatively, all eyes were free of discomfort or significant inflammation and minimal or no topical or systemic anti-inflammatory therapy was required. Abnormal behavior improved or resolved in all cases. In all cats, IOP 24 h after photocoagulation was lower than the postdilation IOP. Cysts did not recur, but new cysts were discovered in several cases. CONCLUSION: Semiconductor diode laser coagulation of anterior uveal cysts is safe, effective and noninvasive.