Subthreshold Micropulse Laser Equivalent to Standard Laser Therapy for DME

Subthreshold micropulse laser therapy was comparable in both efficacy and cost to standard laser therapy in patients with diabetic macular edema (DME) with central retinal thickness less than 400 μm, according to a noninferiority trial published in Ophthalmology.

The multicenter, double-masked trial included 266 patients with central-involved DME less than 400 μm and best-corrected visual acuity (BCVA) greater than 24 Early Treatment Diabetic Retinopathy Study (ETDRS) letters in one or both eyes. Participants were randomized to subthreshold micropulse laser or standard laser treatment.

“Subthreshold micropulse laser therapy was deemed not only noninferior but also equivalent to standard laser therapy because the 95% confidence interval (CI; –3.9 to –0.04 letters) lay wholly within both upper and lower margins of the permitted maximum difference (5 ETDRS letters),” wrote corresponding author Noemi Lois, MD, PhD, of the Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University, Belfast, United Kingdom, and study coauthors.

Between baseline and month 24, the mean ± standard deviation change in BCVA in the study eye was –2.43 ± 8.20 letters in the subthreshold micropulse laser group and –0.45 ± 6.72 letters in standard laser group, according to the study.

Additionally, results showed no statistically significant difference between treatments from baseline to month 24 for the secondary outcomes of binocular BCVA, central retinal thickness, mean deviation of the visual field, percentage meeting driving standards, adverse effects, rescue treatments, or scores on the EuroQoL EQ-5D-5L, 25-item National Eye Institute Visual Function Questionnaire, and Vision and Quality of Life Index.

Researchers further reported no differences in costs or quality-adjusted life-years gained, although the number of treatments was slightly higher in the subthreshold micropulse laser therapy group.

“The latter finding was driven by a small number of participants (n=13) in the subthreshold micropulse laser group who required a larger number of laser treatments,” researchers wrote. “Most participants (approximately 80% and 90% of participants in subthreshold micropulse laser and standard laser groups, respectively) required 1 to 3 laser sessions throughout the 2-year period.”

Reference

Lois N, Campbell C, Waugh N, et al. Diabetic macular edema and diode subthreshold micropulse laser: a randomized double-masked noninferiority clinical trial. Ophthalmology. 2023;130(1):14-27. doi:10.1016/j.ophtha.2022.08.012.