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Nizar Saleh Abdelfattah, Jaya Sadda, Ziyuan Wang, Jewel Hu, Srinivas R. Sadda; Geographic Atrophy Measurements in Fundus Autofluorescence versus Infrared Reflectance Imaging in Dry Age-related Macular Degeneration. Invest. Ophthalmol. Vis. Sci. 2018;59(9):3224.
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© ARVO (1962-2015); The Authors (2016-present)
To compare measurements of area of geographic atrophy (GA) in dry age-related macular degeneration (AMD) obtained by fundus autofluorescence (FAF) and infrared reflectance (IR).
Ninety-seven confocal IR images (Heidelberg HRA + Spectralis) as well as FAF images from 97 patients/eyes with GA from dry AMD were collected retrospectively from existing anonymized Doheny Image Reading Center datasets. Two masked reading center graders (NS and JS) independently and blindly performed manual segmentation of the GA lesions on each IR and FAF image using GNU Image Manipulation Program (GIMP, ver 2.8.22) software. GA on IR/FAF images was defined in accordance to recently published Classification of Atrophy Meeting criteria as sharply-demarcated hyper-reflective regions at least 250 microns in diameter. The difference and point-to-point correspondence between gradings in GA area measurements between IR and FAF were assessed by mean difference, overlap ratio and Dice similarity coefficient.
Among the 97 eyes with dry AMD, mean GA area was 7.62 ± 7.77 mm2 from FAF images and 7.65 ± 7.83 mm2 from IR, with a mean nonsignificant difference of 0.31 ± 0.55 mm2 (two-tailed t-test, p = 0.65). Figure 1 illustrates a typical case with grading result for the each of the two modalities by one of the graders. The overlap ratio in the segmented GA lesion between modalities was 0.84 ± 0.28 with a Dice similarity coefficient of 0.87 ± 0.27. It should be noted, however, that there were 5 cases (5.2%) where the GA lesion could be identified on the FAF image, but not on the IR image.
GA lesions in dry AMD can be identified and quantified reliably using IR images. As IR imaging is comfortable for patients and is commonly obtained along with OCT images, IR-based GA assessment may be a useful surrogate in research studies and clinical trials.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
Figure 1: Example of segmentation of GA lesion on IR and FAF by one grader
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