Treatment of Iris Hypoplasia Using Semiconductor Diode Laser in the Horse Under Standing Sedation

Objective: This study is aimed at describing two unique case presentations of iris hypoplasia and the use of semiconductor diode laser for treatment in the horse. Animals Studied: One 20-year-old American Quarter Horse gelding and one 11-year-old pony mare were studied. Results: The presenting clinical signs, surgical technique, and postoperative results for two cases of iris hypoplasia treated with diode laser are described. Immediate postoperative complications-postoperative ocular hypertension (POH), corneal edema, and epithelial bullae-were possible anticipated effects but were controlled with topical medications in the first case. Following treatment, endothelial contact of the iris was eliminated, and a functional pupil was established in the first case. Anterior synechia occurred long-term but did not lead to pupil obstruction. Left untreated, the iris hypoplasia in the right eye progressed to a degree like that seen upon initial presentation in the left eye. In the second case, the area of the distended, hypoplastic iris was reduced, and the pupil remained functional. Conclusions: Diode laser ablation of hypoplastic iridal tissue was effective at eliminating anterior synechia in both cases presented here. The better functional results in Case 2 suggest that early intervention may result in more favorable outcomes.