Efficacy and safety of subthreshold micropulse laser for chronic central serous chorioretinopathy: a systematic review and meta-analysis

Background Chronic central serous chorioretinopathy (cCSC) can lead to irreversible visual impairment. Traditional treatment methods are limited by their efficacy and the risk of complications. Subthreshold micropulse laser (SML) therapy has emerged as a promising treatment option. Objective This study systematically evaluated the efficacy and safety of SML for treating cCSC, providing evidence-based clinical recommendations. Methods We searched PubMed, Embase, Cochrane Library, and Web of Science for studies published up to January 10, 2025, evaluating SML for cCSC. Eligible designs included randomized controlled trials (RCTs), prospective cohort studies, and case series. Two researchers independently performed literature screening, data extraction, and quality assessment using RoB 2, NOS, and JBI tools, respectively. The certainty of evidence was evaluated using the GRADE system. Meta-analysis was conducted using STATA 18.0 to pool the effects on visual acuity (BCVA) and retinal morphology (CMT, CT, CRT). Subgroup analyses were performed based on laser wavelengths (527, 532, 577, and 810 nm). Results A total of 1,412 articles were identified, and 21 studies were included, with a total sample size of 939 eyes. Meta-analysis demonstrated that SML significantly improved the best-corrected visual acuity (BCVA) of cCSC patients, with a pooled effect size of [SMD = −0.74, 95% CI (−1.14, −0.33), P = 0.001]. The efficacy was consistent across different wavelengths (527, 532, 577, 810 nm). Regarding retinal morphological parameters, SML significantly reduced the central macular thickness [CMT, SMD = −2.15; 95% CI (−3.82, −0.47), P = 0.018], choroidal thickness [CT, SMD = −0.43; 95% CI (−0.79, −0.08), P = 0.025], and central retinal thickness [CRT, SMD = −1.12; 95% CI (−1.34, −0.90), P = 0.001]. Although improvements in subretinal fluid height (SRFH) were not statistical significance, most studies indicated a positive trend. Additionally, SML demonstrated a high safety profile for treating cCSC. Conclusion SML significantly improves visual function and retinal morphology in cCSC patients, demonstrating consistent efficacy across different wavelengths and providing a safe, effective treatment option for cCSC.