Changes in the total area of atrophy in the study and fellow eyes were designated as a secondary outcome of the study. The growth in the area of the GA lesion was monitored with both CFPs and HRA FAF imaging and quantified by masked readers at a reading center. There was excellent agreement between the areas of GA, as quantified by the two imaging modalities (Spearman correlation,
r = 0.986), with areas measured from HRA FAF images being slightly but significantly larger than those measured from CFPs (mean difference [HRA FAF − CFP]) ± SD = 0.178 ± 0.45 mm
2;
P = 0.0001, paired
t-test).
Figures 5A and
5B show the percentage increases in GA area in all participants (
n = 10) at the 2-year time point, as measured from CFPs and HRA FAF images respectively. All study and fellow eyes demonstrated an increase in total GA area from that at baseline, as measured from both imaging modalities. The mean total GA area increased monotonically with time in both the study and fellow eyes, in terms of both mean total GA area (in square millimeters;
Figs. 5C,
5D) and the percentage change of GA area from baseline values (
Figs. 5E,
5F). As measured from CFPs, the mean 2-year increase in GA area was 2.46 ± 1.25 mm
2 (or 1.23 mm
2/y) in the study eyes and 2.47 ± 0.73 mm
2 (or 1.24 mm
2/y) in the fellow eyes. As measured from HRA FAF images, the mean 2-year increase in GA area was 2.17 ± 0.83 mm
2 (or 1.08 mm
2/y) in the study eyes and 2.24 ± 0.91 mm
2 (or 1.12 mm
2/y) in the fellow eyes. Pair-wise comparisons on parameters of (1) change of GA area from baseline at week 104, and (2) percentage change in GA area from baseline at week 104, as determined from both CFP and HRA FAF images, did not reveal any significant differences between the study and fellow eyes (
P > 0.05 for all comparisons). Analysis of differences in 2-year changes in GA area between study and fellow eyes in each participant similarly did not reveal systematic differences (data not shown).
In the 10 participants (20 eyes; 10 study eyes and 10 fellow eyes) analyzed in the study, the location of GA in 4 eyes of 2 participants (participant 9 and 10) were scored as nonsubfoveal at baseline. In participant 9, GA lesions in both the study and fellow eyes remained nonsubfoveal in location by 2 years. In participant 10, GA lesions in both the study and fellow eyes progressed into the center of the fovea by 2 years. In all the remaining eyes (16/20 eyes), the location of GA was subfoveal (i.e., involving the center of the fovea) at baseline.