Efficacy of subthreshold micropulse laser for chronic central serous chorioretinopathy: A meta-analysis

Purpose: To evaluate the efficacy of subthreshold micropulse laser (SML) treatment for chronic central serous chorioretinopathy (CSC). Methods: PubMed, Cochrane Library, and Embase were comprehensively searched for studies published up to April 19, 2021. Randomized controlled trials (RCTs), retrospective and prospective cohort studies that compared SML with any other intervention for chronic CSC were selected. The primary outcomes were best corrected visual acuity (BCVA) and central macular thickness (CMT). Meta-analysis was performed using Review Manager 5.3. Random-effect model was used for pooled analysis. Results: Eleven studies including 834 eyes were included, with 428 eyes undergoing SML treatment and 406 eyes receiving other interventions. Pooled results showed no significant differences between SML and control with respect to BCVA, CMT, or complete resolution of subretinal fluid, while SML treatment was inferior to control in terms of subfoveal choroidal thickness (SFCT) reduction [weighted mean difference (WMD)=44.75, 95% Cl, 14.31-75.20, P<0.05, I2=72%]. However, SML was not superior to photodynamic therapy with respect to SFCT (WMD=61.29, 95% Cl, 29.50-93.08, P<0.05, I2=56%), retinal sensitivity (WMD=-1.85, 95% Cl, -3.05--0.65, P<0.01, I2=0) or NEI-VFQ25 score (WMD=-2.44, 95% Cl, -4.72--0.16, P<0.05, I2=0). No serious side effects of SML treatment were observed.Conclusion: Available evidence suggests that the clinical efficacy of SML therapy is similar to other treatment modalities for chronic CSC. However, because of the lack of serious side effects, SML may be the most promising alternative therapy for chronic CSC. The study protocol was registered on PROSPERO (CRD42021 258837).