In the literature, there is evidence supporting the notion that visual display unit (VDU) use decreases the blink rate and possibly reduces the stability of the precorneal tear film. In this investigation the blink rate and tear stability were measured using noninvasive techniques, in relation to VDU use. In normal healthy subjects, the results show an average 5-fold drop in blink rate during VDU use but tear stability appears to be unaffected. During VDU use a significant relation was found to exist between the interval between blinks and the stability of the precorneal tear film.