[Mean-term variations of visual function of video display terminal operators: observations on 70 cases]

The aim of the study was to evaluate medium-term variations of visual functions in VDT operators and their possible relationship to VDT exposure. The clinical records of 70 VDT operators attending our outpatient service for periodical ergophthalmological evaluation were reviewed in order to evaluate the variation of some visual parameters after a two-years follow-up. These included refraction, phorias, fusional convergence and divergence, stereopsis. The group did not include subjects affected by hyperopia, large ametropias, or binocular vision disturbances and was divided into two subgroups: low exposure group (n = 20; < 4 hours/day) and high exposure group (n = 50; exposure > 4 hours/day). Asthenopia was frequent in both groups. Variation of refraction and binocular vision parameters were absent or rather limited in both exposure groups. This seems to indicate that in subjects without significant ophthalmological problems the risk of permanent functional damage is very low at medium-term.