Effect of Dexamethasone Intravitreal Implant on Visual Acuity and Foveal Photoreceptor Integrity in Macular Edema Secondary to Retinal Vascular Disease

Purpose: The aim of this study was to evaluate the effect of the dexamethasone intravitreal (DEX) implant on the external limiting membrane (ELM) and ellipsoid zone (EZ) integrity in treatment-naive patients with macular edema (ME) secondary to retinal vascular disease (RVD). Methods: This is a 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 1,575.9 +/- 285.9 mu m at baseline to 1,711.7 +/- 244.0 mu m at month 3 (p < 0.0001). Similarly, there was a significant improvement in EZ integrity from baseline to month 3 (1,531.5 +/- 317.1 vs. 1,694.3 +/- 252.8 mu m, 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 mu m from baseline to month 3 (p < 0.0001). Mean changes in VA and CRT were significantly correlated with baseline ELM integrity (p = 0.0065 and p = 0.0046, respectively) and EZ integrity (p = 0.0300 and p = 0.0035, respectively). At month 3, the proportion of eyes which had an intact ELM (mean difference 16.0%, 95% CI 5.4-26.4%, p = 0.0033) and EZ (mean difference 12.0%, 95% CI 1.8-22.1%, p = 0.0210) was significantly higher than at baseline. Conclusions: DEX implant was able to significantly improve ELM and EZ integrity in naive patients with ME.