Micropulse transscleral diode laser cyclophotocoagulation: Short-term results and anatomical effects

Abstract

To evaluate the short-term results of the newly FDA-approved Micropulse transscleral diode laser cyclophotocoagulation (MP-TCP) and its anatomical safety profile based on ultrasound biomicroscopy (UBM) and anterior segment optical coherence tomography (AS-OCT). In this observational study, after topical and periocular anesthesia administration, MP-TCP (MP3 Probe on the Cyclo G6 Laser, Iridex Corporation, Mountain View, CA) was performed in 16 patients. Exposure time was 80 seconds for each 180-degree hemisphere, for a total of 160 seconds and 360 degrees with a power of 2000mW. To evaluate the anatomical impact, UBM and AS-OCT were performed in selected patients pre-laser and 7 days after treatment. Topical steroids were prescribed postoperatively and intraocular pressure (IOP) was monitored as the outcome measure. MP-TCP was conducted in 17 patients, with a mean follow-up period of 35 days. Diagnoses included: 11 primary open angle glaucoma, 1 pigmentary glaucoma, 1 pseudoexfoliation glaucoma, 2 steroid-induced glaucoma, 1 neovascular glaucoma, and 1 normal tension glaucoma. Qualified success was defined as IOP lowering ≥20% with medications, and was achieved in 53% of the cases. Mean pretreatment IOP was 25 mmHg that decreased to 17 mmHg at the end of follow up (p=0.01). There were no significant changes in preoperative (mean 3.5) and postoperative medications (mean 3.0)(p=0.84). No significant changes in visual acuity were observed (p=0.96), and no cases of hypotony or major complications were detected. Anatomical characteristics such as the suprachoroidal space, scleral spur, and angle dimensions were assessed by UBM in 8 patients. AS-OCT was performed in 12 patients to evaluate anterior chamber angle structures, iris features, and the anterior capsule of the lens. No evidence of morphological changes or destruction of adjacent structures were observed. There was also no evidence of suprachoroidal fluid on AS-OCT or UBM. The MP-TCP laser procedure is a promising new treatment for glaucoma that offers a potential safe alternative to more aggressive laser treatment modalities and invasive surgical techniques. No anatomical changes were detected with either UBM or AS-OCT. This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.