High ratio of nonperfusion in severe diabetic retinopathy

Researchers assessed the diagnostic usefulness of retinal nonperfusion to classify diabetic retinopathy severity on OCT angiography.

Study design

This retrospective cross-sectional study evaluated diabetic patients undergoing ultra-widefield OCT angiography imaging at a single retina practice. Images with 100° field of view were obtained from 60 eyes. They were categorized as no retinopathy, nonproliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR). The ratio of nonperfusion (RNP) was expressed as the percent area of capillary nonperfusion within the field of view. It was obtained in the 100° field-of-view image and in concentric sectors encompassing 10°, 10° to 30°, 30° to 50°, and 50° to 100°.

Outcomes

The study showed that the mean RNP from the 50° to 100° sector field of view was 15% for the no retinopathy group, 28% for NPDR group and 42% for PDR group (P<0.01). The field of view detected higher RNP in this sector than in others, regardless of diabetic retinopathy group (P<0.01). It also had the highest optimal sensitivity and specificity for distinguishing NPDR from no retinopathy with a RNP cutoff of 21% and PDR from NPDR with a RNP cutoff of 32%.

Limitations

The limitations of the study are the small number of participants.

Clinical significance

On average, the ratio of nonperfusion is higher in more severe diabetic retinopathy. These findings suggest the most peripheral sector of the widefield OCT angiography (50°-100°) has the most diagnostic usefulness in determining disease severity. With new advancement, OCT angiography can allow for quantification of diabetic retinopathy and better monitoring of disease progression.