Measured power distribution across the Bausch and Lomb Soflens (PAI) Bifocal.

The power distribution across Bausch and Lomb Soflens PAI Bifocal lenses was measured using a series of double aperture stops on a lensometer. The add power at different distances from the lens center is presented. A gradual increase in plus power approximately equivalent to an aspheric back surface of an eccentricity of 0.75 was found. The change in add with change in apical radius (lens distance power) is also reported. The measured change is compared to the calculated power change over the same radius range.