Comparison of Geographic Atrophy Measurements Between Blue-Light Heidelberg Standard Field and Green-Light Optos Ultrawide Field Autofluorescence

Purpose: This study compared geographic atrophy (GA) measurements in the macula using standard 30 degrees field and ultrawide field (UWF) fundus autofluorescence (FAF) imaging.<br /> Methods: Participants from Age-Related Eye Disease Study 2 (AREDS2) and Optos PEripheral RetinA (OPERA) studies with GA were included for comparison between standard field FAF with Heidelberg Spectralis and Optos 200Tx UWF FAF. Two time points 5 years apart were evaluated. GA area (mm(2) ) was recorded in the macular area for both imaging types and in the peripheral field for UWF.<br /> Results: Of 102 paired images (73 subjects), the mean (SD) baseline GA area was 5.32 (6.36) mm(2) with standard and 4.79 (5.87) mm(2) with UWF FAF (P < 0.001). The mean difference between the two modalities was 0.52 mm(2) (95% confidence interval, -2.41 to 1.37). Progression of GA in 25 eyes over 5 years showed a median annual growth rate of 1.28 mm(2) (range, 0.02 to 4.7) for standard and 1.34 mm(2) (range, 0.04 to 5.3) for UWF FAF (P = 0.49).<br /> Conclusions: The measurement of GA is larger on standard than on UWF FAF imaging. The observed difference may be due to image averaging and the use of blue versus green FAF. Similar GA progression with standard and UWF FAF suggests either may be used longitudinally, although not interchangeably. Further investigation is required with updated UWF technology.