Abstract

There are many ways of displaying optical characteristics of a Progressive Addition Lens (PAL). These characteristics are computed by ray-tracing (1).

A short description of a PAL is given. This lens is used for the compensation of presbyopia (2,3). The front surface is a deep non-rotationnally symmetric aspheric designed in order to vary the local power. Then, it allows the presbyope to focus at every distance by changing the gaze. For such an exotic surface, the mathematical model (4,5) is also described.

© 1991 Optical Society of America