Cognitive demand and transient nearwork-induced myopia.

Previous studies have suggested that nearwork-induced myopia may be related to the amount of mental effort and cognitive demand required during the course of near-vision tasks. Accordingly, we compared measurements of the far point of accommodation (FPA) obtained before and immediately after 10-min sustained near-vision tasks involving either low, moderate, or high cognitive demand. All measurements of the FPA were obtained objectively using an open-field infrared optometer. Although a significant myopic shift in the FPA was observed after all conditions, no significant difference was recorded between the three cognitive levels. The mean myopic shift in the FPA immediately after the near-vision task was 0.23 D. It is concluded that the transient, task-induced myopic shift in the FPA is related to the within-task accommodative response rather than to variations in cognitive demand during the course of the near-visual activity.