Quantitative Analysis of Different Foveal Avascular Zone Metrics in Healthy and Diabetic Subjects

The primary aim of this study was to assess the size and shape of the Foveal Avascular Zone (FAZ) in patients with type 2 diabetes mellitus compared to healthy subjects. The study used 80 OCTA images from the FAZID dataset. The FAZ size was measured by its area, perimeter, and maximum/minimum Feret diameters. The shape was assessed using the axial ratio, circularity, roundness, and solidity. These metrics were calculated automatically using Matlab (R) R2020b. Statistical analysis was performed using SPSS statistical software version 28.0, with a p-value of less than 0.01 considered significant. The results showed that the FAZ area was significantly larger in diabetic eyes (mean = 0.50 mm2) compared to control eyes (mean = 0.37 mm2), with a p-value of less than 0.01. Both the maximum and minimum diameters of the FAZ were also significantly larger in diabetic groups compared to the control group. Parameters associated with FAZ's shape were significantly smaller in the diabetic groups than in the control group, except for the axial ratio. The main finding of this study is that diabetic eyes without clinically detectable diabetic retinopathy exhibit morphological changes and irregularities at the FAZ border.