Diabetic Macular Ischemia Diagnosis: Comparison between Optical Coherence Tomography Angiography and Fluorescein Angiography

Abstract

<i>Purpose</i>. To compare fluorescein angiography (FA) and optical coherence tomography angiography (OCTA) images of foveal avascular zone (FAZ) in patients with diabetic retinopathy (DR) with and without diabetic macular ischemia (DMI). <i>Methods</i>. The Wilcoxon signed-rank test was used to compare area measurements and <i>p</i> values of <0.05 were considered statistically significant. FA and OCTA images were independently graded by 2 observers that reached agreement regarding quantitative DMI according established protocols. The ischemic area was divided into "large" macular ischemia (superior to 0.32 mm²) and "small" (inferior to 0.32 mm²) groups. Quantitative analyses of the FAZ were performed using custom software. <i>Results</i>. Thirty-four eyes from 34 diabetic patients were enrolled. Subjects with DMI presented a mean area on FA and OCTA of 0.68 ± 0.53 mm² and 0.58 ± 0.35 mm², respectively (<i>p</i> = 0.1374). Patients without DMI presented a mean area on FA and OCTA of 0.19 ± 0.67 mm² and 0.20 ± 0.79 mm², respectively (<i>p</i> = 0.9594). The ICC for the FAZ measurements between the 2 observers on FA and OCTA was 0.96 and 0.92, respectively. <i>Conclusion</i>. OCTA represents a novel technique for the diagnosis of DMI and it may become an alternative to FA for this purpose.