The measurement of the Bausch & Lomb Soflens contact lens by interferometry

A method is described for the measurement of the anterior and posterior radii of curvature and thickness or a soft (hydrogel) contact lens. The method is based on the observation of an interference pattern that is generated by two beams of light, one reflected from the surface of the lens and the other reflected from the surface of a comparison mirror. It was found that the maximum coefficient of variation for the measured values of the anterior and posterior radii of curvature was 2% and the minimum value was 0.6%. An accuracy of 1:10(3) for the radii of curvature and the center thickness of the lens is claimed.