Transient myopia after visual work

After viewing at near distances for several hours observers may become temporarily myopic. This effect, known as transient myopia after visual work, was studied by measuring contrast sensitivity to a sinusoidally modulated grating pattern. After 3 hours of editing text at a visual display terminal, a significant decrease in sensitivity was found in five subjects out of seven. The results show interpersonal differences in the strength and the time course of work-induced myopia. Measurement of transient myopia by means of contrast sensitivity has the advantage of being rapid enough that even short-term effects can be followed. The decrease in sensitivity can be shown to be a purely optical effect of the eye.