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

Abstract

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. Single-blinded randomized controlled trial. A total of 19 patients with POAG without prior history of incisional glaucoma surgery. 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. Absolute and percentage IOP reduction at 6 months. 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. 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. Proprietary or commercial disclosure may be found after the references.