Success rate evaluation of a simultaneous center add soft contact lens

Abstract

This study has evaluated the success rate of a simultaneous vision center add soft contact lens using two different center-zone sizes. Fifty subjects were included in this study. Each was asked to wear a pair of Spectrum bifocals, with the 2.3 mm center zone in the distance dominant eye and the 3.0 mm center zone in the nondominant eye, for a period of 6 months. Visual acuity, stereoacuity, biomicroscopy, and pupil measurements were evaluated. The results show that 50% of the subjects were successful wearers when two different center-zone sizes were worn. Success rate improved to 67% when those subjects considered failures, either because of near or distance vision complaints, were refitted with two equal center-zone sizes (2.3 or 3.0 mm). We also found that unacceptable near vision was the most common cause of failure.