Prognostic value of shape-descriptive factors for the progression of geographic atrophy secondary to age-related macular degeneration by Pfau, M, Lindner, M, Goerdt, L, Thiele, S, Nadal, J, Schmid, M, Schmitz-Valckenberg, S, Sadda, SR, Holz, FG, Fleckenstein, M, Fundus Autofluorescence in Age-Related Macular Degeneration Study Group