Bilateral Fixed Dilated Pupils after MicroPulse Transscleral Cyclophotocoagulation: A Case Report and Review of Urrets-Zavalia Syndrome

MicroPulse transscleral cyclophotocoagulation (MP-TSCPC) is a relatively new procedure for treating refractory advanced glaucoma. It uses repetitive micropulses of diode laser in an "on-off" cyclic manner, delivered with the Cyclo G6 Glaucoma Laser System (IRIDEX Corp., Mountain View, CA). In this unique case, we report the only instance of bilateral Urrets Zavalia Syndrome (UZS) in medical literature following MP-TSCPC in a 33-year-old Asian female with refractory angle-closure glaucoma. The patient developed bilateral fixed dilated pupils (UZS) after the treatment. The treatment settings included 100 seconds of laser application (50 seconds superiorly and 50 seconds inferiorly). Treated areas were the superior and inferior 180 degrees of the eye, excluding the 3 and 9 o'clock positions. On the first postoperative day, vision and intraocular pressure (IOP) were stable. Six weeks postoperatively, the patient presented with fixed mid-dilated pupils bilaterally and a visual acuity (VA) of 20/200 and 20/300, despite discontinuing Atropine 1% for 42 days. The patient was given pilocarpine 2% for ten days without response; however, vision improved to 20/125 and 20/160 with refraction and a +4.50 add for near vision. One and a half years postoperatively, the patient showed spontaneous partial recovery of the fixed dilated pupils in both eyes, with sectoral paralytic iris superiorly. The overall pupils' size was smaller in both eyes compared to previous visits. This case outlines the patient's symptoms, treatment, and outcome while discussing the potential risk of UZS following MP-TSCPC in specific populations. Further research is needed to better understand and mitigate the UZS complication after MP-TSCPC.