The stability of binocular fixation during reading in adults and children.

The authors recorded the binocular eye-movements of children and adults while they read single words appropriate for their reading ability. Normal data were obtained from nine- to 11-year-old primary-school children and adults, because very little is known about changes in binocular vergence during reading. These normal data were compared with those from poor readers of the same age who had passed or failed the Dunlop Test. On average, normal children made larger vergence errors while they fixated words than did adults. There were no differences between the groups of children, therefore the authors conclude that poor vergence control during reading fixations is not the immediate cause of the non-word error effect found among children who fail the Dunlop Test.