This paper describes an investigation into a possible reduction in visual acuity (VA) and contrast sensitivity from oblique and tinted windscreens. Visual problems in reduced lighting conditions (driving at dusk and at night or in fog) are caused by a reduced contrast in the visual object. In this test subjects with normal vision were tested, together with drivers who already had reduced VA and are only just fit for driving under normal conditions. Test results show that the mean contrast sensitivity of the test persons with VA=0.5 is 3% at the maximum level of luminance used, i.e. already one unit below that of normal persons (4%). A reduction in luminance entails a marked reduction in contrast sensitivity for both groups. There is a clear indication that at a low level of luminance the blue glass causes a greater reduction in contrast sensitivity than the green.
Samenvatting