TABLE 1.

Description of Choriocapillaris Impairment and Geographic Atrophy Growth Metrics

Parameter	Metric	Description
CC impairment analysis
Global CC impairment	Global flow deficit percentage (%)	Global CC impairment was measured by computing the CC OCTA flow deficit percentage over the entire field-of-view, excluding artifacts and lesion interiors (Figure 2D)
Zonal CC impairment	Iso-distance zonal flow deficit percentage (%)	Zonal CC impairment was measured by computing the CC OCTA flow deficit percentage within iso-distance zones, excluding artifacts and lesion interiors. Iso-distance zones were delimited by contours positioned at equally spaced distances from the GA margin in steps of 250-μm (Figure 2E). For multifocal lesions, iso-distance zones from different lesion components were combined
Local CC impairment	Local flow deficit percentage (%)	Local CC impairment was measured by computing, for each point along the baseline GA margin, the CC OCTA flow deficit percentage within a 250-μm diameter disk centered at that point, excluding artifacts and lesion interiors (Figure 2F)
GA growth analysis
Global GA growth rate	Square root area growth rate (mm/year)	The square root area growth rate (Figure 3B) was defined as: $\frac{\sqrt{\text{Follow-Up GA Area}}-\sqrt{\text{Baseline GA Area}}}{\text{Time Between Visits}}$
Local GA growth rate	Growth trajectory Analysis (mm/year)	For each point on the baseline margin, the local GA growth rate was computed as the length of that point’s growth trajectory divided by the intervisit time, as described in the Methods section and Figure 3C-E

CC = choriocapillaris; GA = geographic atrophy; OCTA = optical coherence tomography angiography.