title: Conversion of statistics calculated from the coordinates of the power matrix to those of principal meridional representation of power.
abstract: Principal meridional powers of thick astigmatic systems, like the eye, are not necessarily at right angles. The consequence is a class of phenomena included in the category commonly described as irregular astigmatism. The conventional principal meridional representation of power, however, is unsuited to quantitative analysis. The coordinates of the power matrix are scalars well suited to quantitative analysis. In a sizeable sample of such data it would be tedious to contemplate all the individual observations to obtain knowledge of the material. A standard summary in a manageable form is needed for concise reliable description to deal with all of the data. This paper is concerned with measures of dispersion of a data sample of coordinates of the power matrix, conversion to dispersion of principal meridional representation of power (or any other clinical or scientific power representation), and the nature of the dispersion.
authors.affiliation: School of Computational and Applied Mathematics, University of the Witwatersrand, Private Bag 3, Wits, South Africa. herven.abelman@wits.ac.za
authors.forename: H
authors.initials: H
authors.lastname: Abelman
authors.forename: S
authors.initials: S
authors.lastname: Abelman
mesh_terms: D001251:Astigmatism / Q000503:physiopathology*; D003315:Cornea / Q000502:physiology*; D019781:Corneal Topography; D003627:Data Interpretation, Statistical; D006801:Humans; D008954:Models, Biological; D015233:Models, Statistical; D055095:Optics and Photonics; D012029:Refraction, Ocular / Q000502:physiology*