COMPARISON OF 3 MM × 3 MM VERSUS 6 MM × 6 MM OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY SCAN SIZES IN THE EVALUATION OF NON-PROLIFERATIVE DIABETIC RETINOPATHY.

Purpose: To evaluate the utility of different optical coherence tomography angiography scan protocols in evaluating retinal changes in non-proliferative diabetic retinopathy. Methods: Patients were imaged with the RTVue XR Avanti OCT 3 mm x 3 mm and 6 mm x 6 mm "Angio Retina" scan protocols. Ability to clearly delineate the foveal avascular zone (FAZ), FAZ remodeling, microaneurysms, capillary nonperfusion, motion, and doubling artifacts were evaluated. Results: Forty-six eyes from 27 patients were enrolled. Eighty-nine percent of 3 mm x 3 mm versus 59% of 6 mm x 6 mm scans clearly delineated the FAZ (P = 0.001). Eighty percent of 3 mm x 3 mm versus 43% of 6 mm x 6 mm scans demonstrated FAZ remodeling (P = 0.0002). Microaneurysms were detected by 57% of 6 mm x 6 mm and 35% of 3 mm x 3 mm scans (P = 0.003). Capillary nonperfusion was detected in 87% of 3 mm x 3 mm scans versus 89% of 6 mm x 6 mm scans (P = 0.99). No significant differences were noted in the incidence of artifacts between the scan sizes (motion artifact P = 0.29 and doubling artifact P = 0.29). Conclusion: 3 mm x 3 mm scan delineated FAZ and remodeling better than 6 mm x 6 mm scan, likely because of its higher scan density. 6 mm x 6 mm scans detected microaneurysms more readily than 3 mm x 3 mm, likely because of its larger scan area. There were utility for both 3 mm x 3 mm and 6 mm x 6 mm scans when evaluating these patients.