Visual Efficiency and Fatigue during the Afternoon Shift

For one week, four times a shift, six female machinists were tested for visual fatigue. Three methods were used: convergence and accomodation reading, blink rate, and visual information transfer efficiency. Decrement of convergence and accommodation performance, as well as a higher number of faults and a lengthening of reading time, were found. Increase of blink rate was another result. The importance of the first two methods is stressed as such a diagnosis takes only a short time and can be done directly at the work-place, giving a reliable picture of the visual well-being of the subject