Subthreshold micropulse laser combined with anti-vascular endothelial growth factor therapy for diabetic macular edema: a systematic review and meta-analysis

Purpose To evaluate the effects of subthreshold micropulse laser (SML) in addition to anti-vascular endothelial growth factor (VEGF) therapy for diabetic macular edema (DME). Methods MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were systematically searched for studies that compared anti-VEGF with SML and anti-VEGF monotherapy for DME. Outcome measures were best-corrected visual acuity (BCVA), central macular thickness (CMT), and the number of anti-VEGF injections. Results Eight studies including 493 eyes were selected. Four studies were randomized controlled, and the other four were retrospective. Meta-analysis showed that there was no significant difference in BCVA (mean difference [MD] -0.04; 95%CI -0.09 to 0.01 logMAR; P = 0.13;). CMT was thinner in the group of anti-VEGF with SML (MD -11.08; 95%CI -21.04 to -1.12 mu m; P = 0.03); however, it was due to a single study that weighed higher, and the sensitivity and subcategory analyses did not support the finding. The number of anti-VEGF injections was significantly decreased in the group of anti-VEGF with SML (MD -2.22; 95%CI -3.02 to -1.42; P < 0.0001). Conclusion Current evidence indicates that adding SML to anti-VEGF therapy could significantly reduce the number of anti-VEGF injections compared to anti-VEGF monotherapy, while achieve similar BCVA and CMT.