Visual detection and adaptation to optically induced curvature distortion Does curvature distortion govern progressive addition lens tolerance?

Abstract

We attempt to test the hypothesis that patients who fail to tolerate spectacle lenses may do so as a result of their inability to adapt to the induced curvature distortion. Detection of an adaptation to optically induced curvature distortion occurs to a variable extent among a subject population [I. Rock, The Nature of Perceptual Adaptation (Basic Books, New York, 1966)]. Some patients find progressive addition spectacle lenses (PAL's), which are used for the correction of presbyopia, a difficult type of lens to wear, possibly because of the peripheral distortion shown by the lens. [Ophthal. Physiol. Opt. 9, 163 (1989)]. Two presbyopic subject samples (N = 20) of those who successfully adapted and those who failed to adapt to PAL's are presented, and the variation in the detection of and the adaptation to optically induced distortion of a single line are studied with Gibson's wedge prism approach (J. Exp. Psychol. 16, 1 (1933)]. A third sample (N = 20) of prepresbyopes is included as a control group. This study shows that the detection of and the adaptation to optically induced curvature distortion, as assessed with monocular vision, does not govern patient tolerance. Significant age-related differences in the rate of adaptation are noted between presbyopes and prepresbyopes.