Measures of tear exchange under rigid contact lenses: Part I. The method

Abstract Although previous tear-exchange measurements under contact lens have been primarily qualitative in nature, Cuklanz and Hill in 1969 proposed a mathematical model to determine tear exchange based on particle movement. They first tested that model utilizing flame photometry to determine the number of particles in a given sample. The considerable sample dilution required at that time diminished the accuracy attainable. Recently available nanoliter sample freezing-point osmometry techniques, however, are introduced here to reexplore the CuklanzHill mathematical model more precisely.