Effects of strabismus surgery on choroidal blood flow: a systematic review and meta-analysis

Strabismus surgery may affect choroidal circulation, with potential implications for outer retinal nourishment and visual function. We conducted a systematic review and meta-analysis to quantify postoperative changes in subfoveal choroidal thickness and vascularity parameters following strabismus surgery. A systematic search was conducted in PubMed, Scopus, and Web of Science. After two-stage title/abstract and full-text screening, eligible observational studies reporting pre- and postoperative optical coherence tomography (OCT) or OCT angiography (OCTA) choroidal measures were included. Random-effects meta-analyses estimated pooled mean differences for subfoveal choroidal thickness (SFCT), choroidal vascularity index (CVI), foveal choriocapillaris vessel density (VD), and choriocapillaris flow. Subgroup analyses, meta-regression, quality assessment using the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool, and evaluation of publication bias were performed. Eighteen studies met the inclusion criteria. Pooled analysis of 22 groups (14 studies) showed no significant overall change in SFCT after strabismus surgery (mean difference − 1.13 μm; 95% CI − 6.93 to 4.67; p = 0.70; I2 = 52.1%). CVI (seven groups, five studies) showed no significant change (pooled mean change 0.001; 95% CI − 0.006 to 0.008; p = 0.70; I2 = 0.04%). Foveal choriocapillaris VD and flow showed no significant pooled changes, though choriocapillaris VD exhibited substantial heterogeneity (I2 = 87.9%). Meta-regression detected no associations with follow-up duration, surgical procedure, or number of muscles. No clear publication bias was observed. Current observational evidence suggests no consistent alterations in SFCT, CVI, or choriocapillaris vascularity metrics during the intermediate postoperative period following strabismus surgeries.