[Evaluation of refractive values in patients working for several years at video display terminals. A long-term study].

The authors discuss whether working at a VDT (video display terminal) over a period of years causes non-reversible changes in refraction, especially if it induces a drift towards myopia. A total of 107 persons who had been working at VDT for many years were examined at 2-year intervals and the observations compared with those recorded in 69 persons who had never worked at a VDT. Changes in the correction strengths of their spectacles were evaluated. The statistical analysis was done by chi-square value determination and the Mann-Whitney U-test. The special lens values (diopters) showed no significantly different development in the two groups. It can therefore be concluded that VDT work does not cause myopia to worsen. The cylindrical lens values on the other hand differed significantly in the two groups. This is most probably because any inadequacy in the correction of visual acuity will be noted more easily by persons involved in VDT work.