Grading of Age-related Maculopathy for Epidemiological Studies: Is Digital Imaging as Good as 35-Millimeter Film?

Abstract

Abstract: : Purpose: To evaluate the influence of stereo digital images as compared to stereo 35-mm color film on the quality and reliability of grading age-related maculopathy (ARM) in the context of a multicenter European study (EUREYE). Methods: Digital and 35-mm film stereoscopic fundus images were obtained from 137 eyes with varying degrees of ARM, including no ARM. The images were taken with the same Topcon fundus camera. Two experienced graders classified all signs of ARM according to the International Classification System. Agreement between imaging techniques and between graders was calculated using the weighted kappa statistic. Main outcome measures were: Signs of ARM (number, size and morphology of drusen, pigmentary changes, geographic atrophy, and neovascular macular degeneration), as well as an overall staging system of increasing ARM severity. Results: The weighted kappa value for between-technique agreement ranged from 0.41 for number of drusen <63mm to 0.79 for drusen type and total area occupied by drusen. The kappa for atrophic and neovascular end-stage ARM was 0.87 and 0.94, respectively. The between-technique agreement on stages of ARM was around 0.76. The agreement between graders was largely the same for both techniques of imaging. Conclusions: In the described setting, digital images were as good as 35-mm film for the grading of ARM. Considering the practical advantages of digital imaging, this technique may serve well in epidemiological studies of ARM.

Keywords: clinical (human) or epidemiologic studies: sys • age-related macular degeneration • imaging/image analysis: non-clinical