Effect of driver distraction and low alcohol concentrations on useful field of view and frequency-doubling technology perimetry.

PURPOSE: To investigate the effects of a mental psychometric task that simulates the distraction effect of a hands-free mobile phone and of low alcohol concentrations (0.3-0.5 g/l) on two tests: the useful field of view (UFOV) and frequency-doubling technology (FDT) perimetry.

METHODS: Thirty-seven healthy young vehicle drivers aged 22 +/- 3 years were subjected to a computer version of the UFOV test and FDT perimetry, undertaken according to a counterbalanced within-subject design. The tests were performed in two sessions (an 'alcohol session' and a 'sober session'), while undertaking or not undertaking a psychometric test [the Paced Auditory Serial Addition Test (PASAT)] to simulate the effect of distraction. Each subject was instructed to concentrate on the PASAT while taking each test.

RESULTS: UFOV scores were affected when the PASAT was performed simultaneously (P < 0.0001) in that longer times were required to identify a central target and the location of a peripheral target. FDT perimetry was affected by the addition of the PASAT, with a significant reduction in mean sensitivity and a localized sensitivity loss [pattern standard deviation (PSD) >6 dB]. Test times, false-positive and negative catch trial responses were all increased. However, the UFOV test and FDT perimetry results were not significantly affected by a low alcohol concentration.

CONCLUSION: Distraction significantly affects performance in the UFOV test and frequency-doubling technology perimetry. Our findings suggest that using a hands-free mobile phone while driving may lead to a low-to-moderate crash risk in young adults with normal visual function.