title: Clinical application of the oxygen transmissibility of powered contact lenses.
abstract: Stipulation of the oxygen transmissibility (Dk/L) of a contact lens based upon oxygen permeability (Dk) and nominal lens thickness (L) can be misleading since center thickness, average thickness, and hence Dk/L of a contact lens vary with lens power. While earlier confusion regarding determination of Dk has now been resolved, this data has yet to be fully incorporated into a clinically applicable model. We developed a graphical solution describing variations in Dk/L with power for a representative sample of currently available hydrogel and rigid contact lenses. The Dk/L is found to be optimal for lenses of low minus power (approximately -2.50 D). The model presented here will assist practitioners in assessing the potential oxygen performance of different lens designs with respect to a given power. We advocate that lens manufacturers print the average Dk/L on lens packaging, according to the model described in this paper, along with the parameters that are usually stated.
authors.affiliation: Department of Optometry, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: N A
authors.initials: NA
authors.lastname: Brennan
authors.forename: N
authors.initials: N
authors.lastname: Efron
authors.forename: B A
authors.initials: BA
authors.lastname: Weissman
authors.forename: M G
authors.initials: MG
authors.lastname: Harris
mesh_terms: D003263:Contact Lenses, Hydrophilic; D006801:Humans; D008954:Models, Biological; D055095:Optics and Photonics; D010100:Oxygen / Q000032:analysis*
chemical_list: D010100:Oxygen