Abstract
Abstract: :
Purpose: Visual performance is impaired under conditions of divided attention although most standard tests of vision do not take this into account. The aim of this study was to develop a divided attention (DA) version of a standard visual field test. We then compared performance between standard and DA conditions. Methods: Two lasers projected small spots to either the left or right of a standard fixation target in a Humphrey Field Analyzer (Series VI). In DA conditions, in addition to responding to the peripheral targets, subjects responded to asynchronously-presented central laser spots with a second hand-held response button. Manual response time to central targets and the visual field were recorded. The central detection and visual field tests were also run separately, and manual response time and visual field recorded respectively. Ten young subjects (aged 18-35 years) with normal vision and baseline fields were assessed. Results: The mean test time for the standard 30-2 threshold programme increased slightly in DA conditions (8.120.85 vs. 8.480.92 mins, p=0.333). There were no significant differences in the mean threshold values of standard versus modified visual fields. The mean manual response time for the central detection task increased significantly when combined with the visual field threshold programme (344.9849.7 vs. 492.839.49 secs, p=0.005). Conclusion: When visual field and central detection tasks are combined visual fields are not compromised, although the time taken to complete the task increases slightly. It remains to be seen whether this is also the case with a more demanding central task (e.g. a discrimination task). Visual function declines from early middle age accompanied by increased reaction times, general psychomotor slowing and cognitive changes relating to attention. This may lead to a reduced ability to perform two tasks simultaneously. The next stage of this study will be to investigate the effect of divided attention on visual fields in a group of elderly subjects.
Keywords: 624 visual fields • 310 aging: visual performance • 356 clinical (human) or epidemiologic studies: systems/equipment/techniques