Change in Dynamic Visual Acuity (DVA) by Pupil Dilation

Abstract

Objective: This study was conducted to assess dynamic visual acuity (DVA) under pupil dilation. Background: Pupil dilation may negatively affect driving performance. Methods: Thirty healthy young adults (mean age 29.4 years) with pupil dilation participated in this study as the Mydrin P group. In addition to them, 15 healthy young adults (mean age 28.5 years) without pupil dilation were enrolled as the control group. DVA was measured binocularly with free-head viewing at 0, 30, 60, 120, and 360 min after mydriatic drop instillation in both eyes. Pupil size was measured at each time. Results: In the Mydrin P group, DVA significantly improved at 30, 60, and 120 min (ANOVA; p < .01) but returned to the predilation level at 360 min (ANOVA; p = .61). Pupil size changed from 4.1 to 7.8 mm (ANOVA; p < .01) at 30 min after the instillation, and this level was maintained up to 120 min but returned to normal within 360 min. In the control group, DVA did not significantly change at all measured times (ANOVA; p > .9). DVA was significantly ( p < .05) correlated with the pupil size at all measured times. Conclusion: The improvement in DVA was related to the enlargement of the pupil. This study suggests that the pupil size is one factor that may affect DVA. Application: Potential applications of this study include useful information to assess the effect of pupil dilation on driving performance.