Effect of dexamethasone intravitreal implant on visual acuity and foveal photoreceptor integrity in macular edema secondary to retinal vascular disease

Abstract

Purpose: To evaluate the effect of the dexamethasone intravitreal (DEX) implant on the external limiting membrane (ELM) and ellipsoid zone (EZ) integrity in treatment naïve patients with macular edema (ME) secondary to retinal vascular disease (RVD). Methods: Retrospective study conducted on patients with ME secondary to RVD, who underwent a DEX implant. Results: One-hundred eyes were included. Mean age was 70.3±11.1 years. Mean ELM integrity significantly improved from 1575.9±285.9 μm at baseline to 1711.7±244.0 μm at month 3, p<0.0001. Similarly, there was a significant improvement in EZ integrity from baseline to month-3 (1531.5±317.1 μm versus 1694.3±252.8 μm, respectively, p<0.0001). At month 3, mean visual acuity (VA) gain was 9.9±14.1 letters, p<0.0001. Mean central retinal thickness (CRT) significantly decreased by -193.2±185.7 μm from baseline to month-3, p<0.0001. Mean change in VA and CRT were significantly correlated with baseline ELM integrity (p=0.0065 and p=0.0046, respectively) and EZ (p=0.0300 and p=0.0035, respectively) integrity. At month-3, the proportion of eyes who had an intact ELM (mean difference 16.0%, 95% CI: 5.4% to 26.4%, p=0.0033) and EZ (mean difference 12.0%, 95% CI: 1.8% to 22.1%, p=0.0210) was significantly higher than at baseline. Conclusions: DEX implant was able to significantly improve ELM and EZ integrity in naïve patients with ME.