Impact of Cognitive Demand during Sustained Near Tasks in Children and Adults

Abstract

Accommodation is more accurate and less variable when children are engaged in the task. Children also have more variable accommodation than adults. In addition, children with greater hyperopia have more variable accommodation during sustained near tasks.

Impact of Visual Cues on the Magnitude and Variability of the Accommodative Response in Children With Emmetropia and Uncorrected Hyperopia and Adults

“…Our study is not without limitations. The first limitation of the study is that cycloplegic SE was measured on the Grand Seiko auto-refractor, whereas all experimental measures were captured using the PowerRef II 22. Most children had dilated pupil sizes of >8 mm, which is outside of the operating range of the PowerRef II and, thus, cycloplegic measures were taken using the Grand Seiko.…”

“…The PowerRef II (Plusoptix, Inc., Atlanta, GA, USA) was used to dynamically record accommodative responses during the experiments and only provides measures of refraction in the vertical meridian. Thus, the back-transformed mean RE from cycloplegic autorefraction in sphero-cylinder form was used to calculate the power in the vertical meridian (090) of the eye (described below) to combine the cycloplegic auto-refraction and power refraction measures within each subject to calculate the total accommodative response of the subject 22…”

“…Accommodative lag was calculated as mean difference between the average RE during the experiment and the accommodative demand (100 or 33 cm). The total accommodative response was calculated as the difference between the cycloplegic RE in the vertical meridian of the right eye obtained from Grand Seiko auto-refraction and the accommodative measures derived from the RE measures obtained by the PowerRef II during all conditions 22. For example, if the average of the vertical meridian of the PowerRef II is −2.50 D and a subject has 2 D of uncorrected hyperopia obtained by Grand Seiko auto-refraction, the accommodative lag would be 0.50 D (3 − 2.50 D) and the total accommodative response would be 4.50 D (+2.00 D − (−2.50)).…”

“…Although previous reports exist of the impact of various visual cues on accommodative microfluctuations, many of these past studies have been conducted on adults and, thus, little is known about the impact of visual cues, such as blur or disparity, on accommodative microfluctuations in the developing visual system. Young children with uncorrected hyperopia are of particular interest given that they have larger accommodative demands than their emmetropic peers and have been shown to have increased accommodative microfluctuations when they accommodate to compensate for their hyperopic defocus 21,22. Additionally, because children with larger amounts of hyperopia have greater amounts of defocus to overcome, it is important to understand the relative role of blur and disparity cues on the overall accommodative response.…”

Objective User Visual Experience Evaluation When Working with Virtual Pixel-Based 3D System and Real Voxel-Based 3D System

“…It has been reported that the mean accommodative response is significantly increased during active cognitive tasks [25]. Accommodative microfluctuations has also been investigated in relation to cognitive demand [26,27]. Several studies [21,28,29] have shown an increase in accommodative microfluctuations with increasing accommodative demand.…”