Comparison Of Blue-Light Autofluorescence and Ultrawidefield Green-Light Autofluorescence for Assessing Geographic Atrophy

Abstract

Purpose : The goal of this study was to evaluate and compare the inter-modality and inter-reader agreement of manual and semiautomated GA area measurements in eyes with GA due to age-related macular degeneration (AMD) using conventional blue and UWF green light fundus autofluorescence (FAF) systems.

Methods : FAF images of eyes with GA were obtained during a single visit using both the Spectralis HRA+OCT2 device and the Optos California device. Images were exported for masked analysis by two independent masked graders. The area of the GA lesion(s) was segmented and quantified (mm²) with a fully manual approach where the lesions were outlined using Optos Advance and Heidelberg Eye Explorer (HEYEX) software. In addition, for the Heidelberg blue FAF images, GA lesions were also measured using the instrument’s semi-automated software (Region Finder 2.6.4). For comparison between modalities/grading method, the mean values of the two graders were used. Intraclass correlation coefficients (ICC) were computed to judge the agreement between graders.

Results : 63 eyes of 43 patients were included in this study. The ICC values showed nearly perfect agreement between graders for each modality (0.995 for manual Optos Advance, 0.996 for Heidelberg HEYEX manual, 0.995 for Heidelberg Region Finder). The Pearson's correlation coefficients revealed highly significant positive correlations, with a coefficient of 0.991 (p < 0.001) for the comparison between manual HEYEX and manual Optos, 0.971 (p < 0.001) for Region Finder versus manual HEYEX, and 0.954 (p < 0.001) for Region Finder versus manual Optos. The mean area differences between the Heidelberg manual vs Region Finder, manual Optos vs Region Finder, and manual Optos vs manual Heidelberg were 1.59 mm²(p<0.001), 0.89 mm² (p<0.001), 0.7 mm² (p<0.001) respectively. Bland-Altman plots were generated to illustrate the level of agreement (Figure1).

Conclusions : We observed excellent inter-reader agreement for measurement of GA using either 30 degree blue FAF or UWF green FAF, establishing the reliability of UWF imaging for macular GA assessment. While the absolute measurements between devices were strongly correlated, they differed significantly, highlighting potential differences in approaches to managing image magnification and scaling between devices.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.