The impact of contact lens wear on tear film function of visual display terminal workers

Abstract

Objective To study the effects of contact lens wear on tear film function of visual display terminal (VDT) workers.Methods In this prospective case-control trial,a total of 140 patients (280 myopic eyes) were divided into three groups:group A (56 cases) that were engaged in VDT work no less than 5 hours a day and had wore contact lenses at least one year,group B (45 cases) that were engaged in VDT work no less than 5 hours a day and had never wore contact lenses,and group C (39 cases) that were engaged in VDT work less than 2 hours a day and had wore contact lenses at least 1 year.Schimer I test (SIt),tear break-up time (BUT) and fluorescein (FL) stain were measured among three groups.Results The BUT value was 6.2±2.9s in group 1,7.2±4.0s in group 2,8.0±4.3s in group 3 (P =0.005).The BUT value in group A was significantly lower than that in group B and group C,there were no significant differences between group B and group C.There were no significant differences in SIt and FL stain among three groups.Conclusions Long-term VDT work impairs the function of tear film.People who wear contact lenses suffer more changes on tear film function than those who never wear contact lenses when they are engaged in long-term VDT work. Key words: Contact lens; Video display terminal; Tear film