LENS ADHERENCE AND POSTLENS TEAR FILM CHANGES IN CLOSED-EYE WEAR OF HYDROGEL LENSES

Background. Lens adherence and a reduced postlens tear film circulatio n have been suggested as factors contributing to some adverse reaction s in extended wear of hydrogel contact lenses, In this study, we deter mined lens fitting and postlens tear film characteristics during close d-eye wear, Methods, Twenty subjects wore hydrogel lenses for 3 h of e ye closure, followed by 30 min of open-eye wear, Lens movement was mea sured with a video biomicroscope. Postlens tear film appearances in sp ecular reflection were classified as either amorphous, or as one of fo ur color intensity grades, where a colored appearance was taken as ind icative of a depleted postlens tear film. Results, All subjects showed lens adherence (movement < 0.1 mm) and postlens tear film depletion w ithin 45 min of eye closure, These changes were sustained for the rema inder of the closed-eye period, but were reversed within 15 min of eye opening, Lens adherence was associated with colored postlens tear fil m patterns of any intensity, Conclusion. Closed-eye wear was invariabl y associated with the onset of lens adherence and postlens tear film d epletion, This finding emphasizes the need for adequate lens movement during the open-eye phase of extended wear.