Angioplex metrix

All OCT and OCTA images were obtained using a Cirrus 5000 HD-OCT model (Carl Zeiss Meditec, Dublin, CA, USA). Structural OCT scanning protocols included 6 × 6 mm Macular Cube 512 × 128 cube scans, and OCTA scanning protocols included 3 × 3 mm cube scans centered by foveal fixation. OCT and OCTA image quality check was performed and scans with presence of artifacts, segmentation errors, or signal strength index (SSI) < 7 were excluded from analysis. Structural OCT measurements included central retinal thickness (CRT), macular volume (MV), and average macular thickness (AMT). OCTA quantifications were performed by the built-in commercial software AngioPlex Metrix (v2017, Carl Zeiss Meditec, Dublin, CA, USA) in the superficial capillary plexus of the study eyes, defined by the internal limiting membrane and the inner plexiform layer boundaries. OCTA measurements included vessel density (VD), perfusion density (PD) and foveal avascular zone area (FAZa, mm²), perimeter (FAZp, mm), and circularity (FAZc, %). No manual adjustments of the segmentation slab were performed.

All OCTA and OCT images were obtained using the same OCT device (Cirrus HD-OCT model 5000; Carl Zeiss Meditec, Dublin, CA). OCTA scanning protocols included 3 × 3 mm and 6 × 6 mm cube scans centered in the fovea by gaze fixation (Fig. 2). Structural OCT protocol included a macular cube scan (512 × 128). OCTA and OCT images with presence of artifacts, segmentation errors, or a signal strength index (SSI) < 7 were excluded from analysis. OCTA quantifications were performed by the device built-in commercial software (AngioPlex Metrix, Carl Zeiss Meditec, Dublin, CA) only in the SCP of the study eyes, defined as the layer between the internal limiting membrane (ILM) and the inner plexiform layer (IPL) boundaries. AngioPlex Metrix measurements included vessel and perfusion density and FAZ parameters (area, perimeter, and circularity) displayed for 3 × 3 mm and 6 × 6 mm scans. Vessel density is the total length of perfused vasculature per unit area in the region of measurement; perfusion density is the total area of perfused vasculature per unit area in the region of measurement. No manual adjustments of the segmentation slab boundaries were performed during the conduction of this study. A detailed description of OCTA images included and excluded from analysis is presented in Figure 1.

All OCTA images were captured in 3 × 3 mm cube scans using the same OCT device (Cirrus HD-OCT model 5000, Carl Zeiss Meditec, Dublin, CA, USA). OCTA quantifications were performed by the device built-in commercial software (AngioPlex Metrix, Carl Zeiss Meditec, Dublin, CA, USA) in the superficial capillary plexus (SCP). Measured variables included: vessel density (VD, mm⁻¹), perfusion density (PD, ratio) and foveal avascular zone (FAZ) parameters: area (FAZa, mm²), perimeter (FAZp, mm) and circularity (FAZc, ratio) (Figure 1). OCTA image quality check was performed and scans with presence of artifacts, segmentation errors or signal strength index (SSI) < 7 were excluded from analysis.