Tear exchange under soft contact lenses: An interdisciplinary approach to clinical problem solving

COLL 43

Kenneth A. Polse1, Meng C. Lin1, Kimberly Miller1, and Clayton J. Radke2. (1) School of Optometry, University of California, Berkeley, 525 Minor Hall, Berkeley, CA 94720-2020, (2) Chemical Engineering Dept, University of California, Berkeley, UCB Campus, Gilman Hall, #101, Berkeley, CA 94720-1462
Ocular complications from contact lens wear (CLW) are caused by a combination of metabolic (i.e., corneal hypoxia) and mechanical factors (i.e., lens-cornea interactions). When lenses are worn during sleep, accumulated metabolic debris is removed after eye opening by tear mixing from lid-induced lens motion. We hypothesize that a low clearing rate of tears after eye opening allows debris to remain sandwiched between the lens and eye, causing corneal trauma, and therefore timely removal of debris is a prudent requirement for safe CLW. In this paper we report tear mixing estimates obtained from currently available and experimental lens designs and use these results to examine a recently reported mixing model which suggests that increased transverse lens movement reduces tear clearing times under the lens. Our engineering-clinical collaboration has been valuable in developing lens designs to optimize tear mixing during contact lens wear.