SUBTHRESHOLD MICROPULSE DIODE LASER VERSUS CONVENTIONAL LASER PHOTOCOAGULATION FOR DIABETIC MACULAR EDEMA: A Meta-Analysis of Randomized Controlled Trials

Abstract

Purpose: To evaluate the relative efficacy of subthreshold micropulse diode laser versus conventional laser photocoagulation for the treatment of diabetic macular edema.

Methods: A comprehensive literature search was conducted to find relevant randomized controlled trials (RCTs). Efficacy estimates were determined by comparing weighted mean differences of the mean change of best-corrected visual acuity and central macular thickness from baseline.

Results: Six RCTs were selected for this meta-analysis, including 398 eyes (203 eyes in the subthreshold micropulse diode laser group and 195 eyes in the conventional laser group). Subthreshold micropulse diode laser was superior to conventional laser in terms of mean change of logMAR best-corrected visual acuity at 3, 9, and 12 months after treatment (P = 0.02; P = 0.04, and P = 0.03, respectively), and it showed a similar trend at 6 months (P = 0.05). Although, there was no significant difference in terms of mean change in central macular thickness from baseline to 3, 6, 9, or 12 months (P = 0.80; P = 0.20; P = 0.88, and P = 0.86, respectively).

Conclusion: Subthreshold micropulse diode laser treatment resulted in better visual acuity compared with conventional laser, although the differences before 12 months are likely to be too small to be of clinical relevance and may be dependent on baseline best-corrected visual acuity. The two types of treatment seem to have similar anatomical outcome.