The quantitative OCTA parameters evaluated at baseline were the foveal avascular zone (FAZ) area, the perfusion density (PD), and the vessel length density (VLD) at the whole retina vasculature slab.
The qualitative OCTA parameters included the presence of suspended scattering particles in motion (SSPiM), FAZ erosion, and nonperfusion areas (NPAs) in the whole retina vasculature slab, as well as the MAs visualization both in the SVC and DCP.
The quantitative OCTA parameters were measured as follows: the OCTA whole retina vasculature slab was opened on FIJI (an expanded version of ImageJ: 2.0.0-rc-69/1.52p; National Institutes of Health) [19 (link)], the FAZ border was manually outlined, and the surface area, expressed in mm2, was measured as previously reported [20 (link)]. In addition, the slabs were binarized to generate a black and white image for measuring the PD, and then the images were skeletonized to calculate VLD [20 (link),21 (link)]. The PD defines the ratio of the area occupied by the vessels divided by the total area, providing complete vasculature information in terms of size and length [21 (link)]; the VLD defines the total vessel length divided by the total number of pixels in the analyzed skeletonized image [22 (link)] and may be more sensitive to the microvasculature changes [21 (link)].
The OCT and OCTA qualitative parameters were independently evaluated by two expert readers (EC and MP), and the interclass correlation coefficient (ICC) was calculated. In case of disagreement, a third reader (DDG) assigned the final grade.
All OCT and OCTA parameters included in our analysis were evaluated at baseline to explore their influence on the DEXi 4-months response.
The qualitative OCTA parameters included the presence of suspended scattering particles in motion (SSPiM), FAZ erosion, and nonperfusion areas (NPAs) in the whole retina vasculature slab, as well as the MAs visualization both in the SVC and DCP.
The quantitative OCTA parameters were measured as follows: the OCTA whole retina vasculature slab was opened on FIJI (an expanded version of ImageJ: 2.0.0-rc-69/1.52p; National Institutes of Health) [19 (link)], the FAZ border was manually outlined, and the surface area, expressed in mm2, was measured as previously reported [20 (link)]. In addition, the slabs were binarized to generate a black and white image for measuring the PD, and then the images were skeletonized to calculate VLD [20 (link),21 (link)]. The PD defines the ratio of the area occupied by the vessels divided by the total area, providing complete vasculature information in terms of size and length [21 (link)]; the VLD defines the total vessel length divided by the total number of pixels in the analyzed skeletonized image [22 (link)] and may be more sensitive to the microvasculature changes [21 (link)].
The OCT and OCTA qualitative parameters were independently evaluated by two expert readers (EC and MP), and the interclass correlation coefficient (ICC) was calculated. In case of disagreement, a third reader (DDG) assigned the final grade.
All OCT and OCTA parameters included in our analysis were evaluated at baseline to explore their influence on the DEXi 4-months response.
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