Quantitative assessment of radial peripapillary capillary plexus vessel density after retrobulbar block in cataract surgery: a randomized controlled trial

To evaluate the effect of retrobulbar anesthesia administered before phacoemulsification on radial peripapillary capillary (RPC) plexus vessel density (VD) using optical coherence tomography angiography (OCTA). In this prospective randomized comparative study, 72 consecutive patients undergoing phacoemulsification were randomly assigned to topical anesthesia ( n = 36) or retrobulbar anesthesia ( n = 36). OCTA imaging was performed preoperatively and repeated at postoperative week 1 and month 1. En face OCTA scans centered on the optic nerve head (4.5 × 4.5 mm) were used to quantify RPC plexus VD automatically using AngioAnalytics™ software. The primary outcome was change in RPC VD over time. Between-group and longitudinal comparisons were performed, including repeated-measures analysis to evaluate group-by-time interactions. No significant changes in RPC plexus VD were observed within either group at postoperative week 1 or month 1 compared with baseline (all p > 0.05). Likewise, no significant differences were detected between the topical and retrobulbar anesthesia groups at any evaluated time point or in the magnitude of VD change from baseline to month 1 (all p > 0.05). Effect size analyses demonstrated only small between-group differences, and all corresponding 95% confidence intervals included zero. Repeated-measures analysis revealed no significant group-by-time interaction for any RPC VD parameter (all p > 0.05). Retrobulbar anesthesia was not associated with detectable persistent changes in RPC plexus VD at postoperative week 1 or month 1 after uncomplicated phacoemulsification. No clinically meaningful differences in RPC VD were observed between retrobulbar and topical anesthesia. Further studies incorporating earlier postoperative OCTA assessments are warranted to evaluate potential transient vascular effects. ISRCTN Registry, ISRCTN13084070. Registered on 26 June 2026; retrospectively registered.