Rapid detection of changes in the optic disc: stereochronoscopy. II. Evaluation technique, influence of some physiologic factors, and follow-up of a case of choked disc.

A simple device for viewing stereochronoscopic (Sc) picture pairs under any azimuth is described. The influence of pulse, irradiation, time, and ocular pressure on disc configuration of some healthy and affected subjects is investigated. To test the sensitivity of Sc as compared to that of conventional steroscopy (St), a case of choked disc in which pictures of both kinds had been taken was followed up. This material also served to test 10 observers as to their ability to detect St and Sc effects in fundus pictures. Despite good stereo vision in all observers as tested by the Titmus charts, considerable differences were found in the analysis of fundus pictures. Detailed instruction resulted in improved results. Two cases of glaucoma simplex incipiens are presented in which a change of disc configuration could be detected by SC while ocular pressure and visual field remained normal in one case and did not change in the other.