En Face Swept-Source Optical Coherence Tomography Detecting Thinning of Inner Retinal Layers as an Indicator of Capillary Nonperfusion

Abstract

Purpose To report en face swept-source optical coherence tomography (SS-OCT) as a noninvasive detection modality for regions of retinal layer thinning that are potential indicators of retinal nonperfusion areas (NPAs) in patients with branch retinal vein occlusion (BRVO). Methods Thirty-one eyes of 46 patients with BRVO showing a definite retinal NPA larger than 1 disc in diameter within the vascular arcades were included in this study. We calculated the overlapping correspondence ratio between presumed NPA, which appeared as a dark area in en face SS-OCT, and definite NPA in corresponding fluorescein angiography (FA) images. The correlation between brightness in en face SS-OCT images and corresponding ganglion cell complex (GCC) thickness determined by SD-OCT GCC maps was evaluated as well. Results Measured NPA size in FA and presumed NPA size in en face SS-OCT showed strong correlation (r = 0.746, p<0.001) and colocalization. Reliable agreement between the 2 methods was confirmed by size comparisons (p = 0.11), with an overlapping correspondence ratio of 0.73. Conclusions The results suggest that en face SS-OCT is a noninvasive and relatively reliable method for delineating retinal thinning as an indicator of NPAs in eyes with BRVO. Because SS-OCT can be performed without mydriasis, this procedure may be an option for evaluating NPAs on a screening basis and during follow-up to reduce the number of FA examinations that carry very rare, but potentially fatal, allergic side effects.