Impact of simulated visual impairment on the cognitive test performance of young adults

Aims. This study investigated the effect of simulated visual impairment on the speed and accuracy of performance on a series of commonly used cognitive tests. Methods. Cognitive performance was assessed for 30 young, visually normal subjects ( M =22.0±3.1 years) using the Digit Symbol Substitution Test (DSST), Trail Making Test (TMT) A and B and the Stroop Colour Word Test under three visual conditions: normal vision and two levels of visually degrading filters (Vistech TM ) administered in a random order. Distance visual acuity and contrast sensitivity were also assessed for each filter condition. Results. The visual filters, which degraded contrast sensitivity to a greater extent than visual acuity, significantly increased the time to complete ( p <.05), but not the number of errors made, on the DSST and the TMT A and B and affected only some components of the Stroop test. Conclusions. Reduced contrast sensitivity had a marked effect on the speed but not the accuracy of performance on commonly used cognitive tests, even in young individuals; the implications of these findings are discussed.