Association of Disorganization of Retinal Inner Layers with Ischemic Index and Visual Acuity in Central Retinal Vein Occlusion

Abstract

Purpose To determine whether disorganization of retinal inner layers (DRIL) on optical coherence tomography (OCT) is associated with ischemia on ultra-widefield fluorescein angiography (UWFFA) and with visual outcomes in eyes with acute, treatment-naïve central retinal vein occlusion (CRVO). Design Retrospective, single-institution, longitudinal cohort study. Participants Twenty-five consecutive patients with treatment-naïve CRVO and ≥ 1 year follow-up. Methods Two independent masked graders evaluated the extent of DRIL, ellipsoid zone disruption, external limiting membrane disruption, and other OCT parameters at the baseline, 6- month, 12-month, and final visits. Baseline UWFFA images were assessed for ischemic index values and foveal avascular zone (FAZ) enlargement. Main Outcome Measures Associations of DRIL with UWFFA findings and clinical outcomes including corrected visual acuity (VA). Results The median time to final follow-up was 24 months (range 12.1 – 43.9 months). Median DRIL extent at baseline was 765 µm (range 0 – 1000 µm). Eighteen of 25 eyes (72%) had some degree of DRIL at baseline, and 20 of 25 eyes (80%) had cystoid macular edema (CME). Neither the presence nor extent of DRIL at baseline was associated with presenting VA. In a cross-sectional analysis of each visit, extent of DRIL correlated with worse VA at both the 6-month (ρ = 0.656; p = 0.001) and final (ρ = 0.509; p = 0.016) visits. At final follow-up, DRIL extent was the OCT parameter most strongly correlated with baseline ischemic index (ρ = 0.418; p = 0.047) and baseline enlarged FAZ (p = 0.057) on UWFFA. On multivariate regression analysis, DRIL extent at final follow-up was the only OCT parameter associated with worse VA (p = 0.013) and remained significant when accounting for CME as a potential confounder. Conclusions Extent of DRIL was not associated with presenting VA in treatment-naïve eyes with acute CRVO. Following six months of follow-up however, DRIL extent correlated with worse VA and was predictive of worse VA throughout more than 2 years of follow-up. Ischemic features on UWFFA at baseline are predictive of the extent of DRIL development at final follow-up.

Ultra-widefield retinal imaging: an update on recent advances

“…44 Baseline retinal ischemia demonstrated by UWF-FA is strongly associated with disorganization of retinal inner layers, which in turn is predictive of worse visual acuity at follow-up. 45…”

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

“…Multiple studies have already investigated biomarkers and microvascular morphology of retinal ischemia [ 3 , 4 ]. Quantifying vascular remodeling in retinal ischemic diseases has shown that specific OCT and OCTA variables, which are FAZ, DRIL length, VD, EZ disruption, central subfield thickness (CST) and intra retinal cysts are correlated with visual function.…”

“…Morphological OCT parameters, ELM and EZ disruption, HRF and DRIL have all been described as markers for visual outcome and ischemia in DR and RVO [ 3 , 13 , 22 , 23 ]. In patients with existing or resolved center-involving diabetic edema, DRIL was found to be a prognostic marker of visual outcome.…”

“…Several optical coherence tomography (OCT) features such as external limiting membrane (ELM) disruption, ellipsoid zone (EZ) disruption, hyperreflective foci (HRF) and disorganization of retinal inner layers (DRIL) were described as predictors of retinal ischemia. Also, they were found to be associated with visual acuity [ 3 ]. Consistent relationship between foveal avascular zone (FAZ) enlargement and visual function decrease was shown in multiple studies based on patients with DR and RVO [ 4 , 5 ].…”

New Landmarks, Signs, and Findings in Optical Coherence Tomography

“…Several hypotheses explain the pathogenesis: mechanical factor (stretching of bipolar axons by edema) and vascular factors (ischemia, loss of the retinal capillary plexuses, or neuroglial degeneration as sequelae of inflammation) [58][59][60][61][62]. DRIL has been described as a strong predictive factor of worse visual acuity in patients with DME [58], uveitic macular edema [63], and central retinal vein occlusion [64]. Although the role of ischemia in DRIL is being studied, authors have found that areas of macular capillary nonperfusion were strongly correlated with DRIL on fluorescein angiography (FA) in severe nonproliferative and proliferative diabetic retinopathy (PDR) [59].…”