MicroPulse Transscleral Laser Therapy Dosimetry Utilizing the Revised P3 Delivery Device: A Randomized Controlled Trial.

PURPOSE: To compare the long-term effectiveness and safety outcomes of 2 treatment dosages of the MicroPulse Transscleral Laser Therapy (MPTLT) procedure on intraocular pressure (IOP) control in patients with primary open-angle glaucoma. DESIGN: Single-blinded randomized controlled trial. SUBJECTS: A total of 19 patients with POAG without prior history of incisional glaucoma surgery. METHODS: Subjects randomized into 2 treatment groups, 100-second (total energy 78.25 joules [J], fluence 109.2 J/cm2) or 120-second (total energy 93.9 J, fluence 131.0 J/cm2) total treatment duration, underwent the MPTLT procedure with the revised P3 delivery probe delivering 2.5 W energy, 31.3% duty cycle, applied in 3 sweeps per hemisphere, avoiding 3 and 9 o'clock. All subjects were followed at 1, 3, 6, 9, and 12 months to compare reduction in IOP and medication. MAIN OUTCOME MEASURES: Absolute and percentage IOP reduction at 6 months. RESULTS: The treatment groups were similar in age, sex, and stage of glaucoma at baseline (all P > 0.05). The 120-second group had significantly better baseline best-corrected visual acuity (BCVA) and a higher percentage of patients with prior MPTLT therapy (ranging from 4-19 months before study). Significantly greater IOP reduction was noted in the 120-second group compared with the 100-second group at 3 months, with mean IOP reduction of 7.3 ± 4.2 mmHg (vs. 0.9 ± 2.5 mmHg, P = 0.006) and percentage IOP reduction of 32.2% ± 18.3% (vs. 4.1% ± 13.7%, P = 0.007). The 120-second group continued to outperform at 6-month follow-up: mean IOP reduction of 9.0 ± 4.8 mmHg (vs. 0.8 ± 2.5 mmHg, P = 0.016) and percentage IOP reduction of 37.8% ± 19.8% (vs. 3.6% ± 13.3%, P = 0.021). At 12 months, 37.5% and 18.2% of the 100- and 120-second groups, respectively, required an additional IOP-lowering procedure (P = 0.35); however, Kaplan-Meier analysis of time to intervention was not significantly different (P = 0.38). There were no vision-threatening complications or changes in BCVA during the study period. CONCLUSIONS: This study demonstrates a dose-response relationship with improved IOP control and excellent safety profile in patients treated with higher treatment total energy and fluence using the revised MPTLT probe. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.