title: Measurement of mechanical warpage in CR-39 lenses.
abstract: The warpage of CR-39 ophthalmic spherical lenses of a variety of powers and compressed in the radial direction is measured as a function of the applied tangential force. The lenses are cut with circular shape and then mounted on a frame specially designed to measure the tangential force by means of a calibrated coil spring. The measurements are performed with a high resolution micrometer at different points on the lens surfaces. The warpage of the two surfaces of each lens is calculated and then a quantitative value of surface power variation is given. From these data, vertex power and oblique astigmatism variation are shown. Departure of the surfaces from sphere as a function of the applied tangential force is analysed.
authors.affiliation: Optics Department, Universidad Complutense de Madrid, School of Optics, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Alonso
authors.forename: A
authors.initials: A
authors.lastname: Peral
authors.forename: J C
authors.initials: JC
authors.lastname: Sanz
authors.forename: E
authors.initials: E
authors.lastname: Bernabeu
mesh_terms: D005139:Eyeglasses / Q000592:standards*; D008962:Models, Theoretical; D055095:Optics and Photonics