Computerized optic disc analysis with adjunct stereoscopic viewing of disc photographs

We have investigated the potential usefulness of stereoscopic viewing of optic disc photographs in marking the disc margin in computerized analysis with the Rodenstock Analyzer in 48 eyes of 26 patients with ocular hypertension or primary open-angle glaucoma. Marking of the disc margin without Method 1) and with the aid of stereoscopic viewing of disc photographs (Method 2) three consecutive times by one observer at the same sitting, and three subsequent topographic analyses of each method were done on each 48 eyes. The mean intraphotographic variabilities of such optic disc parameters as rim area, and cup volume with Method 2 were significantly less than those with Method 1 overall and in 16 eyes (33%) with poor video images having an ill-defined disc margin (p less than 0.05 for each), but not in 32 eyes (67%) with clear video images having a well-defined disc margin. Furthermore, the mean paired differences of rim area, disc area and cup volume between the two methods (Method 1 minus Method 2) were also statistically significant overall and in eyes with poor video images (p less than 0.05 for each).