Design and Construction of Chart Evaluating Quantity of Vision in Those Wearing Progressive Addition Lenses

Abstract

Background and Objectives: Currently, there is no standard way to check the optimal fitting of Progressive Addition Lenses (PAL) and visual acuity variations when looking at different objects according to PAL’s production mechanism. We need a standard method to control PAL subjectively according to research on its monitoring. These topics are checked in this study. Methods: Two charts was designed for far and near distances using Persian letters and sentences with a logarithmic scale. Twelve subjects wearing PAL sat at 3 m and 30 cm distances, respectively, from far and near charts, and their visual acuity at Primary Position (Pp) and 15° up and down gazes, and 30° right and left gazes with single and progressive lenses were measured. To evaluate the stability of sharpness, measurements were repeated 5 minutes later. Also, to check the accuracy of vision, the measurements were compared to measurements recorded with a portable Rosenbaum pocket vision screener and E chart. Results: The correlations between Persian and E charts with PAL were confirmed in all gazes except pp. Mean visual acuity in all gazes except pp and 15° up gaze showed the difference in these charts. There are also mean differences in all gazes except 15° down gaze in near vision. Conclusion: Persian and Electronic charts are helpful to evaluate the visual acuity of those wearing PAL and fix the above-mentioned problems.