Presence of subretinal fluid at baseline preserves from photoreceptor alterations in diabetic macular edema and cystoid macular edema due to central retinal vein occlusion

Abstract

Purpose : The aim of this study was to analyze retinal morphological differences in photoreceptor integrity in patients with diabetic macular edema (DME) and cystoid macular edema due to central retinal vein occlusion (CRVO) at baseline (BSL) and 3 months (M3) after treatment initiation with anti-VEGF agents with or without subretinal fluid (SRF) at BSL on spectral-domain optical coherence tomography (SD-OCT) images.

Methods : 102 patients (CRVO, n=42; DME, n=60) were analyzed at BSL and at follow-up at M3 by experienced graders of the Vienna Reading Center (VRC) under the supervision of two retinal experts in custom VRC software. The foveal B-scan of SD-OCT macular cube scans (Heidelberg Spectralis, 49 B-scans) was chosen for each patient for analysis and patients were classified into two groups, SRF present or absent. Morphological changes in the central millimeter area such as disruption and thickening of the external limiting membrane (ELM) and of Inner Segment/Outer Segment (IS/OS) line. Statistical comparisons were performed for SRF/no SRF groups at BSL and M3 with Chi-Square-Test.

Results : ELM disruption was significantly less present at BSL (p=0.009) and M3 (p=0.002) in patients with SRF compared to no SRF. 71 (28/43) out of 74 (29/45) patients from both SRF/no SRF groups with an ELM disruption at BSL still had a persistent disruption at M3, while 18 (13/5) disruptions newly developed at M3. There was no significant difference in IS/OS disruption between SRF/no SRF groups at BSL or M3 (40 total number of IS/OS disruption, 23 SRF, 17 no SRF) but IS/OS thickening was more present in the SRF group compared to no SRF at BSL (p<0.00001). This swelling relieved at M3 in 27 out of 29 cases in the SRF group but persists for all 4 cases with IS/OS thickening in the no SRF group (p=0.003).

Conclusions : Presence of SRF seems to play an important role in the preservation and healing process of the photoreceptors layers in diabetic macular edema and cystoid macular edema due to central retinal vein occlusion when comparing patients with and without SRF at baseline. This protective role of SRF could lead to differences in longterm visual acuity outcomes after anti-VEGF treatment.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.