title: The skew ray issue in ocular aberration measurement.
abstract: I investigated the "skew ray" issue with respect to ocular aberration measurement. This arises for aberrometers that can distinguish only radial components of aberrations. Using simulations and Zernike aberrations, I found that rotationally symmetric coefficients are correctly determined but that asymmetric coefficients are underestimated. This underestimation is more pronounced as radial order of the aberrations becomes smaller and as angular dependence of aberrations becomes greater. There is also "leakage" to other orders, and errors are slightly affected by the sampling pattern. Aberrometers that can distinguish only radial components of aberrations do not provide good estimates of asymmetric aberrations.
authors.affiliation: Visual and Ophthalmic Optics Group, School of Optometry and Institute for Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Australia. d.atchison@qut.edu.au
authors.forename: David A
authors.initials: DA
authors.lastname: Atchison
mesh_terms: D001251:Astigmatism / Q000175:diagnosis*; D006801:Humans; D008962:Models, Theoretical; D015203:Reproducibility of Results; D042262:Retinoscopy / Q000379:methods*