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Brandon W. Lee, Zohar Yehoshua, Fernando M. Penha, Phillip J. Rosenfeld, Giovanni Gregori, Paul F. Stetson, William J. Feurer; Comparison of Geographic Atrophy Measurements from the OCT Fundus Image and an Enhanced OCT Fundus Image Derived from the Increased Light Penetration into the Choroid. Invest. Ophthalmol. Vis. Sci. 2011;52(14):142. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To compare the areas of geographic areas (GA) measured on two different types of en face fundus images derived from spectral-domain optical coherence tomography (SDOCT).
Forty-five eyes from 45 patients with geographic atrophy secondary to non-exudative AMD were enrolled in an ongoing prospective SDOCT study at the Bascom Palmer Eye Institute. The eyes were imaged with the Cirrus SDOCT (Carl Zeiss Meditec, Dublin, CA). using the 200 A-scan by 200 B-scan raster pattern contained within a 6mm X 6mm area. The acquired three-dimensional data were then be used to create an en face OCT fundus image (OFI) and an enhanced OFI using only information from bellow the RPE. For inclusion in this study, the GA lesions had to be contained within a 6mmX6mm area centered on the fovea. The GA boundaries were drawn manually by two graders after exporting the files to a CintiQ WACOM digitizing tablet (WACOM Corp., Vancouver, WA). The measurements from enhanced OFI were also obtained using automated software developed by Zeiss.
There was excellent agreement between the two graders measuring the enhanced OFIs (ICC = 0.993) and comparable to that between graders the regular regular OFIs (ICC=0.996). The agreement was reduced, but still very good between each grader and the automated result from the enhanced OFIs (Grader 1: ICC=0.883; Grader 2: ICC= 0.877). The mean (SD [range]) of averaged grader slab measurements was 5.34 mm2 (4.15 [0.16, 16.16.37) and not significantly different from the automated mean of 5.46mm2 (3.14 [0.9, 12.9]) (p=0.69).
Both the OCT fundus image and the enhanced OCT fundus image proved to be useful for identifying and reproducibly measuring GA in AMD. Automated GA measurements using the enhanced OFI provided very similar measurements when compared with manual segmentation. This method should be useful when following patients with GA over time and in future clinical trials on dry AMD.
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