title: Power and tear volume exchanges with flexible contact lenses.
abstract: Mathematical formulas are used to infer volumetric tear exchange from power changes of flexible contact lenses in situ. These calculations are developed from changes along the radius, and must be considered approximate due to several underlying assumptions.
mesh_terms: D003263:Contact Lenses, Hydrophilic / Q000592:standards*; D006801:Humans; D008433:Mathematics; D008962:Models, Theoretical; D055095:Optics and Photonics; D013666:Tears