Ultra-wide-field fluorescein angiography–guided normalization of ischemic index calculation in eyes with retinal vein occlusion

PURPOSE. The purpose of this study was to compare the use of central and montaged ultra-wide-field fluorescein angiography (UWFFA) images for calculating the area of nonperfusion (NP) and ischemic index (ISI) in patients with retinal vein occlusion (RVO) and macular edema (ME) and to correlate these measurements with best-corrected visual acuity (BCVA) and central macular thickness (CMT). METHODS. Thirty eyes of 30 RVO patients with recurrent ME were enrolled. Baseline UWFA images were sent to the Doheny Image Reading Center for quantitative analysis by certified graders. The association between ISI from the various zones and BCVA and CMT was examined by Spearman rank correlation and compared. Generalized linear models (GLMs) were used to analyze associations between BCVA and disease status. RESULTS. The NP area and ISI for central and montaged images were not significantly different for any retinal zone. A modest but statistically significant negative linear correlation was observed between BCVA and ISI, ranging from r = 0.3825 in the perimacular area (PMA) to r = 0.584 in the far peripheral area (FPA). On GLM analysis, both PMA (β = 1.059; 95% confidence interval: 1.74 to 0.378) and FPA (β = 0.505; 95% confidence interval: 0.988 to 0.021) were significant independent predictors of BCVA. We found no correlation between ISI from the various zones and CMT in this cohort. CONCLUSIONS. Montaging of UWFFA images may not be required to adequately quantify and represent areas of NP in eyes with RVO. NP in both the PMA and peripheral retina appear relevant to visual function, highlighting the importance of evaluating the retinal periphery in these individuals.