Identification of microvascular and morphological alterations in eyes with central retinal non-perfusion

PURPOSE: To evaluate the characteristics and morphological alterations in central retinal ischemia caused by diabetic retinopathy (DR) or retinal vein occlusion (RVO) as seen in optical coherence tomography angiography (OCTA) and their relationship to visual acuity. METHODS: Swept-source optical coherence tomography (SSOCT) and OCTA (Topcon, Triton) data of patients with central involving retinal ischemia were analyzed in this cross-sectional study. The following parameters were evaluated: vessel parameters, foveal avascular zone (FAZ), intraretinal cysts (IRC), microaneurysms (MA), vascular collaterals in the superficial (SCP) and deep plexuses (DCP), hyperreflective foci (HRF), epiretinal membrane (ERM), external limiting membrane (ELM) and ellipsoid zone (EZ) disruption, as well as the disorganization of retinal inner layers (DRIL). Best-corrected visual acuity (BCVA), age, gender, disease duration and ocular history were also recorded. RESULTS: 44 eyes of 44 patients (22 with RVO, 22 with DR) were analyzed. The mean age was 60.55 ± 11.38 years and mean BCVA 0.86 ± 0.36 (Snellen, 6m). No significant difference was found between DR subgroups (non proliferative vs. proliferative). Between RVO subgroups (CRVO vs. BRVO) a significant difference was found in term of collateral vessel of the DCP (p = 0.014). A pooled DR and RVO group were created and compared. Significantly more MAs (p = 0.007) and ERM (p = 0.007) were found in the DR group. Statistically significant negative correlation was demonstrated between FAZ and BCVA (p = 0.45) when analyzing all patients with retinal ischemia. CONCLUSION: This study has shown that the best predictor of visual outcome in center involved ischemic diseases is the size of FAZ. Besides the presence of MAs and ERM, all other OCT and OCTA parameters were present in a similar extent in DR and RVO group despite the completely different disease origins. Our results suggest that as soon as retinal ischemia in the macular region is present, it has a similar appearance and visual outcome independently of the underlying disease.