Keratometric variation: the influence of a fluid layer.
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.
Cronje-Dunn
S
S
Department of Optometry, Rand Afrikaans University, Auckland Park, South Africa.
Harris
W F
WF
D006801:Humans; D009907:Optometry / Q000379:methods / Q000592:standards*; D013666:Tears