Abstract

In the quest for a solution to presbyopia and due to the inability to restore the eye's system itself, man in the last centuries resorted to a continuous evolution of increasingly sophisticated types of eyeglasses (Fowler and Patreas, 1991). What technology has had to offer so far, as practical products, were glasses that utilize rigid lenses. The most advanced solution on the market today is spectacles with progressive addition lenses (PAL) that provide a different, yet fixed power, in each direction of gaze. This is still a compromise with the real need of a dynamically varying power. While in some frequently occurring situations, such a grading approximates real needs, in many other situations the compromise forces uneasy head tilting and partially impaired vision.

© 1992 Optical Society of America