Diagnostic Ability of Optical Coherence Tomography Angiography Macula Vessel Density for the Diagnosis of Glaucoma Using Difference Scan Sizes

Abstract

Precis: There is diagnostic information in the outer region of optical coherence tomography angiography (OCT-A) macula scans not available in the inner region, and this information is especially useful in the early stages of glaucoma. Purpose: The aim of this study was to evaluate the diagnostic accuracy of 3x3 and 6x6 mm(2) macula OCT-A scans for classifying healthy, mild glaucoma, and moderate to severe glaucoma eyes. Methods: Participants enrolled in the Diagnostic Innovations in Glaucoma Study (DIGS) with good quality 3x3 and 6x6 mm(2) OCT-A images of the macula acquired on the same day were included in this cross-sectional study. The area under the receiver operating characteristic (AUC) curves were calculated to assess the diagnostic accuracy of vessel density (VD) of both scan sizes for differentiating between 3 diagnostic groups. Results: Two hundred seventy-nine eyes (89 healthy, 127 with mild glaucoma, and 63 with moderate to severe glaucoma) from 190 subjects were included in this study. The VD of the outer area of the 6x6 mm(2) scan size had higher diagnostic accuracy compared with the VD of the inner area of the 3x3 mm(2) scan when differentiating between healthy and mild glaucoma (3x3 mm(2) AUC=0.71 and 6x6 mm(2) AUC=0.79, P=0.032). The VD of the outer area of the 6x6 mm(2) scans had only similar diagnostic accuracy compared with the inner area of the 3x3 mm(2) scan when differentiating between healthy and moderate to severe glaucoma eyes (AUC=0.90 for 3x3 mm(2) and 0.92 for 6x6 mm(2), P=0.279). The VD of the inner area of the 6x6 mm(2) scan size had similar diagnostic accuracy to the corresponding area of the 3x3 mm(2) scan in both diagnostic categories. Conclusion: The diagnostic accuracy of VD using the 6x6 mm(2) macula OCT-A scan was better than the 3x3 mm(2) scan when differentiating between healthy and mild glaucoma eyes, and similar to the 3x3 mm(2) scan when differentiating between healthy and moderate to severe glaucoma eyes.