2008 Volume 29 Issue 3 Pages 86-94
Progressive addition lenses (PALs) have some particular optical characteristics that derive from the corridor of the progressive surface along the meridian of the lens. In this paper, I will talk about the basic specifications and optical characteristics of these lenses. Advances in free-form cutting machines have enabled the fast fabrication of complex surfaces to high precision; consequently, this has led to the development of some new PAL. These are customized lenses whose creation takes into consideration various wearer conditions. Lens design is optimized to provide the best performance for the individual wearer. Some PAL may therefore have lens power information that differs from the usual.
