Measuring the Quality of Drivers’ Night Vision

Abstract

The visual acuity of 30 male and female drivers aged 20-25, 40-45, and 60-65 years was examined under conditions of “high” background luminance, “low” background luminance, and “high” background luminance with added glare. Results illustrate the characteristic decline in visual ability associated with increasing age and decreasing background luminance, and in addition show that strong correlations exist between scores achieved in the various background and glare conditions. Based on the data collected, it is estimated that the proportion of drivers who would fail a 20/40 visual acuity test at a “low” but representative background luminance ranges from less than 10% of the 20-25 year age group to more than 90% of the 60-65 year age group. It is recommended that a testing procedure be made available which would permit drivers to learn the extent of their potential nighttime seeing deficits, especially in the case of professional drivers who may be required to operate at night.