ABSTRACT The posterior surface curvature of eight Bausch and Lomb Soflenses™ was measured by using a Moiré interference fringe technique. This unique method was used to allow measurement of the curvature variation across the lens surface and to provide new information which may be helpful in understanding difficult fitting problems and improving fitting techniques. Central apical curvature values determined from lens measurements agreed with values published by Bausch and Lomb within 6%. Low negative power lenses became steeper, whereas higher minus power lenses became flatter away from the apex toward the lens periphery. However, none of the lenses tested was as flat in, the outer portion of the lens as predicted by hydrodynamic forced‐vortex theory which i should be applicable for spun‐cast fluid lenses. There was also a significant change in curvature, first flattening, then steepening across the lens as it dried out during the course of the measurement.
Bob Gilman (Mon,) studied this question.