Correlation between Visual Acuity and Optical Coherence Tomography Biomarkers in Retinal Vein Occlusion

Abstract

Abstract Purpose: To use optical coherence tomography (OCT) changes in retinal venous occlusive disease (RVO) as biomarkers to predict the visual outcome. Patients and Methods: Patients with recent RVO complicated by macular edema were included in the study. Patients with ocular comorbidities other than RVO and patients with media opacities precluding a clear fundus view were excluded. Initial full clinical assessment including the measurement of best-corrected visual acuity (BCVA) was done. Fundus photography, fundus fluorescein angiography, and OCT were done. The central subfield thickness (CST) was measured. Disruption of the ellipsoid zone (EZ) in the fovea was documented. The ratio between the vertical size of the largest cyst (VSLC) and the maximum macular thickness (MMT) was calculated. Furthermore, the length of photoreceptor outer segment (PROS) was measured. Assessment was repeated at 1, 3, and 6 months. Correlation between those biomarkers and visual acuity (VA) by multiple linear regression analysis was performed at presentation and at the conclusion of follow-up period after treatment completion. Results: Twenty-four eyes of 24 patients (mean age 54.1, 11 males and 13 females) with RVO were included. Mean logarithm of the minimum angle of resolution BCVA was 1.3 ± 0.5. Mean CST was 618 ± 326 μm. At presentation, the strongest correlation with BCVA was with CST ( R = 0.56) followed by interruption of EZ ( R = 0.32), DRIL ( R = 0.31) and the ratio of VSLC/MMT ratio (0.28). There was a weak negative correlation between PROS length and BCVA ( R = 0.1). At the end of follow-up period, the strongest correlation with final BCVA was with ratio between VSLC/MMT reflecting the pattern of cystoid macular edema and Muller cell integrity followed by EZ interruption and DRIL reflecting ischemic insults. Conclusions: Different retinal micro-structural biomarkers can be observed in patients with RVO by spectral-domain OCT. Among those biomarkers, the strongest predictor of VA at presentation is CMT, followed by interruption of the EZ, followed by disorganization of retinal inner layers (DRIL), followed by decreased PROS length. At 6 months’ follow-up, the correlation between ischemic changes, for example, DRIL and interruption of EZ with BCVA becomes more apparent that at presentation.