Layer-Specific Retinal Perfusion as a Personalized Biomarker: Evaluating the Subclinical Microanatomical Effects of...

Background/Objectives: The objective of this study was to evaluate macular perfusion changes after intracameral injection (ICI) of cefuroxime at the end of phacoemulsification. Methods: Patients who underwent routine phacoemulsification were enrolled. Subjects in the case group had ICI 1 mg/0.1 mL cefuroxime at the end of surgery. Using optical coherence tomography angiography (OCT-A), macular perfusions were assessed at T0 (before surgery), T1, T10, T30, and T90 (days after surgery). Perfusion parameters were calculated in the superficial capillary plexus (SCP) and the deep capillary plexus (DCP). Independent t-tests were used to compare the changes from baseline in each parameter between groups. Results: A total of 33 eyes in the case group and 27 eyes in the control group were enrolled. After surgery, the case group showed a less pronounced reduction in the foveal avascular zone (FAZ) in the DCP at T10 (-0.06 ± 0.23 vs. -0.18 ± 0.18 mm², p = 0.041) and T30 (-0.04 ± 0.20 vs. -0.16 ± 0.24 mm², p = 0.050). At T90, there was no statistically significant difference in the FAZ change in the DCP between the groups. The postoperative changes in the vessel density, skeleton density, and acircularity index of the FAZ in the SCP and DCP, central retinal thickness, and best-corrected visual acuity were similar between the groups in all 3 months. Conclusions: Our findings indicate that intraoperative ICI low-dose cefuroxime is associated with a temporary deceleration in FAZ reduction in the DCP during the first postoperative month. From a personalized medicine perspective, these layer-specific microanatomic variations suggest that, while prophylactic cefuroxime is globally safe-demonstrating no evidence of inducing capillary dropout, aggravating macular thickening, or compromising visual outcomes within this cohort-preoperative and postoperative OCT-A monitoring can serve as an individualized screening framework to track subclinical perfusion dynamics, especially in patients with compromised retinal baselines.