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Maximilian Pfau, Moritz Lindner, Lukas Goerdt, Steffen Schmitz-Valckenberg, Srinivas R Sadda, Frank G Holz, Monika Fleckenstein; The perimeter as predictor for the progression of geographic atrophy (GA) secondary to age-related macular degeneration (AMD). Invest. Ophthalmol. Vis. Sci. 2016;57(12):1613.
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© 2017 Association for Research in Vision and Ophthalmology.
Natural history studies in geographic atrophy (GA) secondary to AMD show a high variability in rates of lesion progression over time. Previously identified prognostic markers include size of baseline GA, lesion circularity and FAF patterns. The aim of the current study was to evaluate the perimeter of the GA area at baseline as a prognostic marker for atrophy enlargement rates in a longitudinal natural history study.
A total of 50 eyes of 42 patients (mean age 74.21±6.69) participating in the prospective natural history FAM- (“Fundus Autofluorescence imaging in Age-related Macular Degeneration”, NCT00393692) and DSGA- (“Directional Spread in Geographic Atrophy”, NCT02051998) studies were included in the analysis. Quantification of atrophy was performed based on fundus autofluorescence imaging and using the RegionFinder software (Heidelberg Engineering, Germany). The graded annotated images were transferred to ImageJ (Bethesda, Maryland, USA) to measure the area, circularity and perimeter of the lesions. Scaling-factors for the pixel-to-µm conversion were obtained from the HEYEX software (Heidelberg Engineering, Germany).
The area of atrophy was positively correlated to the area of upcoming expansion of the lesion (Spearman’s rho 0.228, p=0.006). A higher correlation was observed between the area of upcoming expansion and the circularity (Spearman’s rho -0.424, p<0.001) and the perimeter (Spearman’s rho 0.456, p<0.001), respectively. Further analysis revealed that a decrease in circularity (during the previous interval) was followed by an increase of enlargement rate in the subsequent interval (p<0.05, Pearson's chi-squared test χ2). The circularity of atrophy was significantly decreased in eyes exhibiting the diffuse-trickling (DT) phenotype (0.117±0.118) compared to eyes exhibiting other phenotypes (0.344±0.229, p<0.001, Wilcoxon signed rank test). Eyes with the DT-phenotype exhibited a significantly faster enlargement rate than eyes with other FAF-phenotypes (2.98±0.86mm2 versus 0.89±1.31mm2, p<0.001).
GA progression rates are correlated with the area, perimeter and circularity of the lesion. The findings indicate that spread of GA may be associated with the extent of damaged adjacent retinal pigment epithelium cells.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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