The purpose of this study was to examine the visual function of professional truck drivers at working age to find out whether older drivers had any defective function and should therefore be given less demanding duties at work. Of the 100 drivers invited for the study, 77 came to the examination, including 74 men and 3 women aged from 30 to 66 years (mean 50.3 ± 10.3 years). In addition to the basic eye examination, visual fields, dark adaptation, contrast sensitivity, colour vision, and glare sensitivity were studied. Two drivers (2.6%) had an incipient cataract in one eye, four (5.2%) had slight fundus abnormalities, five (6.5%) had exo- or esotropia, and five (6.5%) had amblyopia. Visual acuity in the better eye varied from 0.4 to 1.2 (mean 1.06 ± 0.17) and in the other eye from 0.1 to 1.2 (mean 0.96 ± 0.23). Five drivers (6.5%) had inadequate visual acuity for a professional driver's license. Visual fields were interpreted as normal in all drivers. The results of the dark-adaptation, contrast-sensitivity, and glare testing showed values within normal ranges for all drivers. In the colour-vision tests, five male drivers (6.8%) had a slight congenital green effect, and two drivers had an acquired blue effect in one eye because of cataract and diabetes. According to the present study, there is no need to give older drivers less demanding duties because of their eyes. However, one serious finding in the present study needs attention: the visual acuity was lower than that required for a professional driver's license in five drivers. Evidently, more regular check-ups of visual acuity are needed for a professional driver's license. (A)
Samenvatting