Abstract
Abstract: :
Purpose: To compare gradings of lesions associated with age–related macular degeneration (AMD) from digital and stereoscopic film images. Methods: Sixty two people were recruited to have retinal images of the disc and the macula captured in both eyes through nonpharmacologically dilated pupils (NPD) and pharmacologically dilated pupils (PD) using a 45° digital camera (6.3 megapixels). In addition, 30° stereoscopic retinal film images were taken through pharmacologically dilated pupils of the same eyes (N=124). All images were graded for drusen size, type and area, pigmentary abnormalities, geographic atrophy and exudative lesions by masked graders using the Wisconsin Age–Related Maculopathy Grading Scheme. Exact agreement and unweighted kappa scores were calculated for gradings resulting from digital and film images. Results: When categorizing AMD as none, early and late, agreement was best between digital (PD) and film images both taken through a dilated pupil (exact agreement (EA) = 91%, kappa = 0.85, standard error (SE) = 0.05). Agreement for grades from NPD images compared to dilated film images was also good (EA = 80%, kappa = 0.69, SE = 0.06) as was agreement for the grades from digital images captured both ways (NPD vs PD – EA = 85%, kappa = 0.77, SE = 0.05).
Kappa scores for specific lesions were best when comparing grades from digital and film images taken through a pharmacologically dilated pupil. However, the comparability was similar for most pair–wise comparisons. When disagreement was present between film gradings and gradings from digital images, either before or after pharmacological dilation, it was most often due to ungradable lesions in the digital images. Conclusions: Gradings resulting from high resolution digital images, especially when the pupil is dilated, are highly comparable to those resulting from film based images. We conclude that digital imaging of the retina is useful for epidemiological studies of AMD.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • age–related macular degeneration