Eye symptoms and reading abilities of computer users subjected to visually impaired direct glare

Abstract

Computer work is a visually demanding task associated with adverse eye symptoms. Frequent use of digital displays is known to cause a deterioration of the so-called binocular control. Direct glare further reduces the capacity for binocular coordination during computer work, leading to reduced reading ability and increased eye symptoms.The purpose of this study was to investigate the effect of different luminance levels of direct glare on binocular eye movement control and reading ability in a computer work environment.Sixteen participants with normal binocular vision performed equal reading tasks in a balanced study. Three controlled lighting conditions of direct glare (2000, 4000 and 6000 cd/m2) were tested, in addition to no glare. After each trial, the participants answered survey questionnaires regarding their understanding of the text, as well as their subjective experience of workload and perceived vision. Horizontal fixation disparity (FD) was measured before and after the reading tasks to evaluate binocular eye movement control.When comparing the responses of visual experience, a significant difference in reported eye symptoms was found between lighting conditions. Based on the variation (SD), a significant difference was found within mean values of repeated measurements of horizontal FD and a significantly higher variation in a comparison of initial FD values measured during lighting conditions of no glare, to final measured values in all three glare conditions. Reading ability was found to be significantly negative affected with the adversity of lighting conditions.This study supports the contention that binocular eye movement control is reduced caused by direct glare. Even lower degree of disability glare caused eye symptoms. The results establish the argument that working with flat screens raises visual demands.