Evaluation of semiautomated measurement of geographic atrophy in age-related macular degeneration by fundus autofluorescence in clinical setting.

PURPOSE To assess intraobserver and interobserver agreement among physicians with different degrees of clinical experience, using a novel fundus autofluorescence semiautomated software for quantification of geographic atrophy in clinical setting. METHODS Fundus autofluorescence frames (excitation: 488 nm; emission: 500-700 nm) of 29 eyes (20 patients; mean age, 79.6 ± 6.2 years) with geographic atrophy secondary to age-related macular degeneration, and no signs of choroidal neovascularization, were analyzed using Region Finder, a semiautomated software embedded in Spectralis (Heidelberg Engineering, Heidelberg, Germany). For each study eye, semiautomated atrophy identification and quantification were independently performed, twice (in a 2-week time frame), by 3 readers with different degrees of clinical experience (2 fellows, and 1 resident). Intraobserver and interobserver agreements were assessed. RESULTS Mean difference in intraobserver agreement (Bland-Altman statistics) ranged from -0.17 mm² to 0.13 mm². Intraobserver agreement was excellent until the geographic atrophy threshold value of 15.72 mm². Variability correlated with the size of atrophy. Mean difference in interobserver agreement (Bland-Altman statistics) ranged from -0.25 mm² to 0.27 mm², with no significant difference between senior and junior readers. Multifocal lesion or foveal involvement in atrophy was not the cause of disagreement. CONCLUSION Region Finder is a reliable tool for the identification and quantification of geographic atrophy in patients with age-related macular degeneration, in a clinical setting even when performed by junior reader.