Comparability of cup and disk diameters measured from nonstereoscopic digital and stereoscopic film images.

Abstract

To compare gradings of optic disk and cup diameters from stereoscopic film and nonstereoscopic digital images. Comparison of techniques. setting: CLINIC-BASED. Right eyes of 62 adults. observation procedures: Images of the disk were taken through pharmacologically dilated pupils with a 45-degree digital camera (6.3 megapixels) and with a stereoscopic 30-degree film camera. Measurements were taken for vertical diameters of optic disks and cups. Agreement of disk and cup measurements and cup to disk ratios. Optic disks and cups were slightly smaller when graded from the stereoscopic film images. Cup-to-disk ratios were similar. Correlations between film and digital images measurements were high. Measurements taken from nonstereoscopic digital images through a dilated pupil were similar to those taken from stereoscopic film images. Lack of stereoscopic effect may lead to small differences in measuring the optic disk and cup diameters. Nonstereoscopic digital imaging may be useful in epidemiologic studies when measures of optic cups and disks are needed.