HYDROGEL (ACUVUE) LENS MOVEMENT IS INFLUENCED BY THE POSTLENS TEAR FILM

The determinants of hydrogel lens movement with thin mid-water content lenses may be better understood by taking into account the lubricatio n properties of the tear film. We assessed lens movement, postlens tea r film (PTF) status, and tear meniscus height with 58% water content ( Acuvue) lenses worn over 6 h on each of 2 consecutive days. Median len s movement was near zero initially and increased within the first hour to 0.34 and 0.30 mm on days 1 and 2, respectively (Friedman analysis of variance by ranks, days 1 and 2, p < 0.001). The small lens movemen t at 15 min was related to the increased PTF depletion (Kruskal-Wallis analysis of variance; day 1, p = 0.02; day 2, p = 0.007). In some sub jects, lens movement and PTF status co-varied throughout the lens wear ing periods. These findings suggest the PTF is a determinant of hydrog el lens movement.