A VARIATIONAL APPROACH TO PROGRESSIVE LENS DESIGN

The ability of the human eye to accommodate (i.e. to see both near and far objects sharply) decreases with age. In order to correct this def ect, so-called progressive-addition lenses (PALs) have been developed. This paper presents a new method for the design and quality control o f PALs. The desired properties of the PAL are combined in an error fun ctional, involving curvature properties of the front surface of the le ns. It is shown how to efficiently minimize this error functional iter atively and we prove quadratic convergence. We also present an efficie nt method for reconstructing the geometry of a manufactured PAL based on sensor data obtained by measuring devices. The combination of geome try reconstruction and optimization provides a useful tool for the mai n design loop of PALs. The system has been developed and implemented i n close cooperation with the optical industry. (C) 1998 Elsevier Scien ce Ltd. All rights reserved.