THE USE OF NEWTONS RINGS FOR CHARACTERIZING OPHTHALMIC LENSES

The interference technique of Newton's Rings is widely used for the qu ality control of optical surfaces because the precision obtained with this method proves to be very satisfactory, The dimensions of the ring s permits calculation of the radii of curvature of the analysed surfac es and deformation of the interference pattern can be utilised to calc ulate other parameters, such as astigmatism. We describe the study of progressive surfaces by means of this technique, whereby the analysis of the various points of the progressive corridor is made, and also in clude information on the power function for these lenses, as well as t he addition and corridor length. (C) 1998 The College of Optometrists. Published by Elsevier Science Ltd. All rights reserved.