Published By James E. Sheedy, OD, PhD, and Ethis Communications, Inc.

In a second PAL rating study, James E. Sheedy and colleagues at the Center for Ophthalmic Optics Research (COOR) at OSU have measured 12 lenses each of 23 different PAL designs and reported upon the sizes of the viewing zones and magnitude of unwanted astigmatism.

COOR has measured the optics of several different progressive lens designs and shown large differences in the sizes of the distance, intermediate, and near viewing zones. Ratings of the various PAL designs were reported in a 2004 publication and updated in a January 2006 publication that is available at: www.optometry.osu.edu/research/coor/