Reliability and Validity of Video Centration Devices While Comparing with Clinical Interpapillary Distance Measurement

Purpose: The purpose of this study was to investigate the reliability and validity of video centration devices when comparing with clinical interpapillary distance instruments. Methods: There were sixty-three university students aged from 20 to 22 with no eye diseases, no strabismus or anisometropia, and also otherwise healthy conditions were recruited in the study. For the purpose of the present study, PD rule, pupilometer (Essilor), and video centration device (Rodenstock ImpressionIST) were operated by a licensed and experienced optometrist. Pearson correlation, ANOVA analysis, t-test, and linear regression were analyzed for explanations. Results: PD ruler, Essilor pupilometer, and Rodenstock ImpressionIST all capture validity and reliability. The accuracy and validity of near PD measurement between PD rule and pupilometer were confirmed; but still existed minor difference between both instruments. Monocular PD measurements showed high correlations but no significant different between pupilometer and video centration devices. Results suggested that it would be concern with the settings of video centration devices system while examination. Linear regression analysis suggested that near and distance pupilometer values might effectively predict the data of video centration devices, cross comparison can avoid the human errors and instrument setting. Conclusion: Clinical instruments are treasure for practical measurement by trained examiners, video centration devices apply another quality and repeatable option for comparing and systematical lens design. Since human errors in the study were still retaining less than 0.5mm, corresponding to the standard prescription, it needed to mention that the probability of human errors might be avoided as much as possible.