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

Abstract

<b><i>Purpose:</i></b> 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-naïve patients with macular edema (ME) secondary to retinal vascular disease (RVD). <b><i>Methods:</i></b> This is a retrospective study conducted on patients with ME secondary to RVD, who underwent a DEX implant. <b><i>Results:</i></b> One-hundred eyes were included. Mean age was 70.3 ± 11.1 years. Mean ELM integrity significantly improved from 1,575.9 ± 285.9 μm at baseline to 1,711.7 ± 244.0 μm at month 3 (<i>p</i> < 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 μm, respectively, <i>p</i> < 0.0001). At month 3, mean visual acuity (VA) gain was 9.9 ± 14.1 letters (<i>p</i> < 0.0001). Mean central retinal thickness (CRT) significantly decreased by –193.2 ± 185.7 μm from baseline to month 3 (<i>p</i> < 0.0001). Mean changes in VA and CRT were significantly correlated with baseline ELM integrity (<i>p</i> = 0.0065 and <i>p</i> = 0.0046, respectively) and EZ integrity (<i>p</i> = 0.0300 and <i>p</i> = 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%, <i>p</i> = 0.0033) and EZ (mean difference 12.0%, 95% CI 1.8–22.1%, <i>p</i> = 0.0210) was significantly higher than at baseline. <b><i>Conclusions:</i></b> DEX implant was able to significantly improve ELM and EZ integrity in naïve patients with ME.