Effect of intravitreal dexamethasone implant in treatment-naive and previously-treated patients with diabetic macular edema

Purpose: To document the effects of intravitreal dexamethasone implant on retinal microvasculature in patients with diabetic retinopathy complicated by center-involving macular edema. Methods: 35 eyes of 35 patients affected by retinopathy due to type 2 diabetes (15 treatment-naïve and 20 previously treated) were included in this retrospective study with a follow-up of 4 months. Foveal avascular zone (FAZ) area and superficial capillary plexus (SCP) and deep capillary plexus (DCP) densities in the foveal and parafoveal areas were measured by optical coherence tomography angiography (OCTA) at baseline and 2 and 4 months post-injection. Intraocular pressure, morphological and functional parameters were evaluated. Results: a significant difference was found in both groups at 2 months after injection in terms of functional (BCVA, p < 0.05) and morphological (CMT, p < 0.05) parameters. During follow-up, FAZ area, SCP, and DCP in the foveal and parafoveal areas did not change significantly. Conclusions: intravitreal dexamethasone implant is effective in the treatment of diabetic center-involving macular edema and was associated with significant improvements in BCVA and CMT at 2 months after injection. After a single dexamethasone implant injection, FAZ area and retinal vascular density does not show significant variations in both naive and non-naive DME patients subgroups.