Comparative investigations of progressive lenses.

Different types of progressive addition lenses were compared with each other. It was our aim to measure all parameters in such a way that they were consistent with the normal wearing situation. The distribution of the spherical power and astigmatism was measured with a special focimeter. The induced distortion, which is important for patient acceptance, was determined by a photographic method. There are significant differences between the various types of progressive addition lenses. However, objective information is not sufficient to resolve the subjective question of patient acceptance.