Faricimab Improves Choriocapillaris Perfusion in Diabetic Macular Edema

This study is a retrospective observational study to evaluate the effects of intravitreal faricimab on choriocapillaris perfusion in diabetic macular edema (DME) using optical coherence tomography angiography (OCTA) and to investigate the relationship between changes in choriocapillaris flow void (CCFV) and visual outcomes.

Eyes with center-involved DME that received four consecutive monthly intravitreal faricimab injections were included. OCTA (Solix FullRange®) was obtained within 1 month before the first injection and 1 month after the fourth injection. The choriocapillaris (CC) slab was segmented per device default, and CCFV was quantified after Phansalkar local thresholding. Additional metrics included central retinal thickness (CRT), subfoveal choroidal thickness (sfChT), and choroidal vascularity index in Sattler's (CVI_S) and Haller's layers (CVI_H). Pre/post differences were tested with paired t-tests, and Pearson correlation analyses were performed to assess the associations of changes in CCFV with changes in structural optical coherence tomography (OCT) parameters and best-corrected visual acuity (BCVA).

Thirty eyes were analyzed. Mean CCFV decreased from 53.35 to 48.89%, yielding a mean reduction of 4.46% (95% confidence interval [CI], -6.37 to -2.56; P < 0.001). BCVA improved significantly (mean difference, -0.20 logMAR; 95% CI -0.27 to -0.12; P < 0.001). CRT decreased from 483.43 ± 72.26 to 313.93 ± 58.41 µm (mean difference, -169.50 µm; P < 0.001). sfChT also decreased significantly (mean difference, -35.56 µm; P < 0.001). CVI_H increased significantly (mean difference, 2.71 percentage points; P < 0.001), whereas CVI_S showed a slight but non-significant increase (mean difference, 0.62 percentage points; P = 0.483). No significant correlations were observed between changes in CCFV and those in CRT, sfChT, CVI_S, or CVI_H (all P > 0.05). However, changes in CCFV were positively correlated with changes in BCVA (r = 0.437, 95% CI 0.091-0.689; P = 0.016), with greater reductions in CCFV associated with greater visual acuity improvement.

Faricimab was associated with a significant reduction in CCFV, suggesting improved choriocapillaris perfusion accompanied by significant anatomical and functional improvements in DME. The significant association between changes in CCFV and visual acuity improvement suggests that OCTA-derived CCFV may serve as a functional biomarker of treatment response. These findings support the concept that restoration of choriocapillaris perfusion may contribute to visual recovery and highlight the role of the choroid in DME beyond retinal edema resolution.