Correlation between Deep Capillary Plexus Perfusion and Long-Term Photoreceptor Recovery after Diabetic Macular Edema Treatment

Abstract

Purpose: To determine the association between baseline deep capillary plexus (DCP) integrity and long-term photoreceptor recovery as well as visual outcome after treatment in patients with diabetic macular edema (DME).

Design: Retrospective, interventional case series.

Participants: Sixty-seven eyes with DME that resolved successfully with initial treatment (baseline) and that remained edema free for 12 months after the initial DME resolution.

Methods: Best-corrected visual acuity (BCVA), spectral-domain (SD) OCT, and OCT angiography findings were collected at baseline and at 6 and 12 months after baseline. Correlations were analyzed between DCP integrity parameters (vascular flow density [VD] and area of the foveal avascular zone [FAZ]) and photoreceptor integrity parameters (ellipsoid zone [EZ] and external limiting membrane [ELM] integrity). Multivariate linear regression analysis was conducted to identify the baseline predictors for photoreceptor recovery and visual improvement.

Main outcome measures: The association between baseline DCP integrity and recovery of photoreceptor integrity over 12 months.

Results: At baseline, the mean central retinal thickness was 306.1±51.8 μm. The mean baseline DCP VD and FAZ were 14.4±5.2% and 0.71±0.36 mm², and the mean baseline EZ and ELM integrity were 57.2±26.1% and 76.4±19.8%, respectively. Ellipsoid zone and ELM integrity recovered significantly at 12 months from baseline (both P < 0.001). The degree of EZ and ELM integrity recovery was well correlated with the baseline DCP VD (P = 0.004 and P = 0.009, respectively) and DCP FAZ (P = 0.007 and P = 0.009, respectively). Moreover, the mean change in BCVA from baseline to 12 months was significantly greater with higher baseline DCP VD (P = 0.003) and smaller DCP FAZ (P = 0.042). Compared with anti-vascular endothelial growth factor (VEGF) nonresponders, anti-VEGF responders had higher baseline DCP integrity and a significantly greater degree of photoreceptor recovery at 12 months.

Conclusions: The degree of DCP preservation at the time of initial DME resolution is correlated closely with long-term recovery of photoreceptor integrity and visual outcome in patients with resolved DME.