Prism Diopter for Unconformity between the Optical Center and the Pupil Center

ABSTRACT

PURPOSE: To investigate the effect of the difference between interoptical and interpupillary center distance on the eye of the patient. METHODS: One hundred patients were enrolled in this study. We investigated the congruities between interpupillary and interoptical center distance, the horizontal balance of optical center, and the induced prismatic effects. RESULTS: Prismatic effects were evaluated for 30 patients who were wearing inaccurate lens centering. The average of P.D in male (64.2+/-2.7 mm) was greater than that in female (61.2+/-2.2 mm). The evolution of the induced horizontal phoria showed that forty-seven percent of the patients had induced exophoria and fifty-three percent of the patients had induced esophoria. The prism diopter of the induced exophoria and esophoria were 0.92+/-0.87delta and 0.62+/-0.46delta, respectively. CONCLUSIONS: When the pupillary distance of or the interpupillary distance was not accurately measured, the prism effect and the induced phoria developed by the difference between interoptical and interpupillary center distance.