title: Keratometric variation: the influence of a fluid layer.
abstract: Variation of keratometric measurements on an approximately spherical surface on a polymethyl methacrylate (PMMA) button is compared to keratometric variation on the PMMA button after the application of an artificial solution. The variation is shown by means of scatter plots in a three-dimensional space, as well as quantitatively in the form of variance-covariance matrices. The wet button showed variances a factor of more than 1000 times that of the dry button. This suggests that the precorneal tear film could be an important, often-overlooked contributing factor to keratometric variation in the case of the eye.
authors.affiliation: Department of Optometry, Rand Afrikaans University, Auckland Park, South Africa.
authors.forename: S
authors.initials: S
authors.lastname: Cronje-Dunn
authors.forename: W F
authors.initials: WF
authors.lastname: Harris
mesh_terms: D006801:Humans; D009907:Optometry / Q000379:methods / Q000592:standards*; D013666:Tears