Diabetic macular edema with neuroretinal detachment: OCT and OCT-angiography biomarkers of treatment response to anti-VEGF and steroids

Purpose: To assess and compare early changes in neuroinflammatory and vascular parameters in diabetic macular edema (DME) with subfoveal neuroretinal detachment (SND) after treatment with intravitreal dexamethasone (DEX-I) and ranibizumab (IVR). Methods: Thirty-three eyes (33 patients) with treatment naïve DME with SND were retrospectively evaluated at baseline and 2 months after DEX-I (15 eyes) and 1 month after 3 monthly IVR injections (18 eyes). Inclusion criteria were: complete eye examination, good quality OCT and OCT-A images. OCT parameters included: central macular thickness (CMT); number of hyper-reflective retinal spots (HRS) in inner, outer (IR, OR) and full retina; choroidal thickness (CT), extent of disorganization of inner retinal layers (DRIL), outer retina integrity (OR). On OCT-A: foveal avascular zone (FAZ) parameters in the superficial capillary plexus (SCP); cysts area and perfusion density (PD) in SCP and deep capillary plexus (DCP) and flow voids (FV) in choriocapillaris. FAZ was analyzed using ImageJ, perfusion parameters and FV using MATLAB. Results: BCVA increased equally after both treatments (13.0 ± 10.0 ETDRS letters, p < 0.0001). There was a similar decrease (p < 0.05) in: height of SND, cysts area at SCP, central and mean CT, increase in FAZ perimeter and OR integrity, after both treatments. A greater decrease in DEX-I versus IVR group was found in: CMT (− 38.7% vs. − 22.2%, p = 0.012), HRS number in IR (− 29.2% vs. − 14.0%, p = 0.05) and full retina (− 24.7% vs. − 8.0%, p = 0.03), DRIL extension (− 62.0% vs. − 24%, p = 0.008), cysts area at DCP (− 68.7% vs. − 26.1%, p = 0.03), FAZ-CI (− 19.1% vs. − 8.3%, p = 0.02), PD at DCP (− 27.5% vs. + 4.9%, p = 0.02). FV did not change. Conclusions: More pronounced changes in specific inflammatory parameters in the inner retina are documented after steroid versus anti-VEGF treatment. These include reduction in HRS number, DRIL extension, CMT, cysts area at DCP. These data may help in further study of noninvasive imaging biomarkers for better evaluation of treatment response