title: Tear exchange and contact lenses: a review.
abstract: Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses.
authors.affiliation: Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Ontario, Canada. Electronic address: amuntz@uwaterloo.ca.
authors.forename: Alex
authors.initials: A
authors.lastname: Muntz
authors.affiliation: Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Ontario, Canada.
authors.forename: Lakshman N
authors.initials: LN
authors.lastname: Subbaraman
authors.affiliation: Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Ontario, Canada.
authors.forename: Luigina
authors.initials: L
authors.lastname: Sorbara
authors.affiliation: Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Ontario, Canada.
authors.forename: Lyndon
authors.initials: L
authors.lastname: Jones
mesh_terms: D003263:Contact Lenses, Hydrophilic; D003315:Cornea / Q000378:metabolism*; D015590:Fluorophotometry; D006801:Humans; D008962:Models, Theoretical; D013666:Tears / Q000502:physiology*
keywords: Contact lens; Fluorescein; Fluoresceína; Fluorofotometría; Fluorophotometry; Intercambio de lágrimas; Lentes de contacto; Película de lágrimas; Tear exchange; Tear film