Estimates of the prevalence of eye problems associated with using visual display terminals (VDTs) vary enormously depending on the sample tested and the research methods employed. However, most authors agree that eye problems are common among VDT users. In this paper, the relative contributions of the nature of VDT displays, workstation design, work-practices and optometric factors are discussed, drawing from the substantial body of literature which now exists on this subject.

A significant number of young school children have unsuspected remediable visual defects. The computer-based vision screener provides an efficient, sensitive and specific method for screening in schools.

Estimates of the prevalence of eye problems associated with using visual display terminals (VDTs) vary enormously depending on the sample tested and the research methods employed. However, most authors agree that eye problems are common among VDT users. In this paper, the relative contributions of the nature of VDT displays, workstation design, work-practices and optometric factors are discussed, drawing from the substantial body of literature which now exists on this subject.

Pupillary responses to brief presentations of sinusoidal grating patterns were measured. The results show that the amplitude of the pupillary responses varies systematically with grating spatial frequency. Gratings of spatial frequencies in the range 1-5 c deg-1 elicited the maximum percentage change in pupil area, with higher and lower spatial frequency gratings producing smaller responses. The bandpass nature of the pupil response function was compared to contrast sensitivity functions obtained under the same viewing conditions. The effects of defocus and eccentric fixation on both contrast sensitivity and pupil response functions were qualitatively similar. Grating acuities calculated from contrast sensitivity data correlated well with similar data extracted from pupil response functions. The results suggest that automated pupillometry can provide an attractive means for objective measurement of visual acuity.

The aim of this study was to carry out quantitative analyses of eye movements during the cover test on a group (n = 57) of asymptomatic emmetropes. Eye movements were recorded during an automated cover test while subjects fixated a distance (3.4 m) and near (0.4 m) target. There was a significant difference between the amplitude of phoria measured after 2 s of occlusion compared to 10 s (P < 0.01). The mean phoria after 10 s of occlusion was 0.1 degree (eso) for distance fixation and 1.6 degrees (exo) for near fixation. The distribution was approximately normal for both distance and near fixation but the standard deviation was greater for near (2.0 degrees) than distance fixation (1.4 degrees). The pattern of eye movements during the recovery phase was more complex than is often assumed, in many cases consisting of a variety of saccadic and vergence movements involving both the covered and 'fixing' eye. The latency of the first recovery movement was significantly shorter for exophoric than esophoric deviations (P < 0.01) and the latency of some recovery movements were very short (< 150 ms).