COMPARISON OF COLOR FUNDUS PHOTOGRAPHS AND FUNDUS AUTOFLUORESCENCE IMAGES IN MEASURING GEOGRAPHIC ATROPHY AREA

Abstract

To assess the agreement between color fundus photographs (CFP) and fundus autofluorescence (FAF) images when measuring geographic atrophy (GA) area and reproducibility of measurements between graders. Frequency and disagreement types were also determined. Eyes with GA secondary to age-related macular degeneration had CFP and FAF imaging on the same day. Seventy-two eyes from 72 patients were included in the analysis. Three graders calculated GA area using digital imaging software. Main outcome measures included agreement between graders for GA area on both FAF and CFP and agreement between both imaging modalities. The intraclass correlation for the 3 graders for FAF images was 0.99 (95% confidence interval, 0.98-0.99). For CFP, it was 0.96 (95% confidence interval, 0.94-0.97). The intraclass correlation between imaging modalities for Graders 1, 2, and 3 were 0.93, 0.85, and 0.87, respectively. Sensitivities to detect involvement of fovea (CFP, 86-97%; FAF, 72-93%) and specificities to detect sparing of fovea (CFP, 74-76%; FAF, 59-88%) overlapped between imaging modalities. Both CFP and FAF imaging are reliable for measuring GA area. Interobserver agreement was slightly higher for FAF images. Although the high agreement between modalities suggests that either would be appropriate for measuring GA area, using both may be the best approach for following GA progression.