The effect of prism adaptation on the response AC/A ratio.
Vergence adaptation, also known as prism adaptation, is a phenomenon in which a patient's heterophoria changes after prolonged viewing through prism. The effect of prism adaptation on the accommodation-convergence relationship, quantified by the AC/A ratio, is not known. Previous studies of AC/A ratio stability and alterability have used only stimulus AC/A ratio calculations, or have measured accommodative responses to only one or two stimuli. The ideal study of AC/A ratio stability and alterability would measure accommodative responses to several accommodative stimuli, and use these along with vergence responses to calculate response AC/A ratios, rather than stimulus AC/A ratios. In addition, the gradient method should be used to avoid any effect of proximal vergence resulting from changes in target distance. This paper describes a project which investigated the effect of vergence (prism) adaptation on the gradient response AC/A ratio, using accommodative responses measured for five different accommodative stimuli. The response AC/A ratio did not significantly change following a period of adaptation to base-in prism for six of the eight subjects in this study. In addition, the response AC/A ratio did not significantly change following a period of adaptation to base-out prism for six of the eight subjects.
Rainey
B B
BB
Indiana University, School of Optometry, Bloomington 47405, USA.
D000065:Accommodation, Ocular / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D003290:Convergence, Ocular / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D055095:Optics and Photonics; D012029:Refraction, Ocular