ABSTRACT
The authors analysed the interpupillary distance, the distance between optical centers and the distance from the upper margin of the lens to the optical center in 297 spectacles wearers. The results were as follows: 1. Among the 297 glasses wearers, myopic glasses wearers accounted for 226 persons(76.09%), and hyperopic glasses wearers for 71 persons(23.91%). 2. Among the 297 glasses wearers, the distance between optical centers coincided with the interpupillary distance in 51 persons(17.17%), and was incongruous in 246 persons(82.83%). 3. Among the 297 glasses wearers, the distance from the upper margin of the lens to the optical center was the same in both eyes in 152 persons(51.19%), and was incongruous in 145 persons(48.81%). 4. Among the 246 persons in whom the distance between optical centers of their glasses did not coincide with the interpupillary distance, the horizontal prismatic effects of both eyes overpassed the aberration of tolerance of ophthalmic dispensing in 46 persons(18.70%), and the maximum horizontal prismatic effect of one eye was 5.85 prism diopters. 5. Among the 145 persons in whom the distance from the upper margin of the lens to the optical center of their glasses did not coincide in both eyes, the vertical prismatic effects overpassed the aberration of tolerance of ophthalmic dispensing in 48 persons(33.10%), and the maximum vertical prismatic effect was 2.47 prism diopters.