LAUSR

Aim . To investigate the relationship between the foveal avascular zone (FAZ) and inner nuclear layer (INL) – free zone in order to provide a personalized approach for evaluation of the FAZ area with optical coherence tomography-angiography (OCTA). Material and methods .Thirty-six healthy individuals (36 eyes) and 9 patients (12 eyes) with nonproliferative diabetic retinopathy (nPDR) were included in this study. The FAZ area as well as INL-free zone were measured in superficial capillary plexus on OCTA images. The FAZ area, INL-free area, and the ratio of the INL-free area to the FAZ area were compared between healthy subjects and nPDR patients. Results . The mean FAZ area in healthy subjects and nPDR patients was 0.33 ± 0.1 and 0.56 ± 0.28 mm2 (p 0.05), respectively. The ratio of the INL-free area to the FAZ area in healthy subjects and nPDR patients was 1.08 ± 0.25 and 0.57 ± 0.2 (p < 0.001), respectively. Receiver operating characteristic analysis showed that the ratio of the INL-free area to the FAZ area had the higher area under curve (0.98; 91.7% sensitivity and 97.2% specificity) compared to the FAZ area (0.8; 66.7% sensitivity and 87.1% specificity) for differentiating nPDR from healthy eyes. Conclusion . This study showed that personalized analysis of the FAZ area based on the relationship between the actual FAZ and INL-free zone has better diagnostic accuracy compared to the conventional FAZ area measurement on OCTA images.