PURPOSE: This study aimed to investigate the effects of extraocular muscle recession performed as part of strabismus surgery on posterior retinal and choroidal blood flow. METHODS: A single-center prospective study was conducted on patients who underwent strabismus surgery. Optical coherence tomography, optical coherence tomography angiography, and laser speckle flowgraphy of the macula were performed before surgery and at one week, one month, and four months after surgery. Preoperative and postoperative ratios were calculated, and longitudinal changes in retinal blood flow, choroidal thickness, and choroidal blood flow were analyzed. Furthermore, the changes based on the types of resected muscle were examined. RESULTS: In total, 254 eyes from 127 patients were included. The subfoveal choroidal thickness increased significantly at one week and one month after surgery, with no significant change at four months after surgery. The choroidal blood flow increased significantly at one week after surgery, with no significant changes at one and four months after surgery. The retinal vessel density significantly decreased at one week after surgery, with no significant changes at one and four months after surgery. Analysis of groups that had various muscles excised showed no significant changes in any measurements. Choroidal thickness and blood flow were significantly correlated at one week after surgery. CONCLUSIONS: Strabismus surgery decreased retinal blood flow but increased choroidal thickness and blood flow in the early postoperative period. Moreover, no significant changes were observed in the long term compared to the preoperative period. TRANSLATIONAL RELEVANCE: Strabismus surgery affects the retina and choroid in the early postoperative period but not in the long term.