Anisophoria and aniseikonia. Part I. The relation between optical anisophoria and aniseikonia.

Part I of this publication demonstrates and explains the close relation between aniseikonia and anisophoria induced by spectacles. It discusses the clinical implications of this relation by discussing certain aspects of aniseikonia theory, prismatic effects during oblique gaze through spectacles as for reading, and a simple formula that presents a comprehensive description of all prismatic effects and prismatic differences produced by a pair of spectacles. It also describes an easy method of specifying iseikonic lenses, as well as some conventional methods of measuring aniseikonia and anisophoria. Part II will deal with the correction and management of anisophoria when induced together with aniseikonia. Parts I and II, together, will convey a new approach toward the management of anisophoric spectacle corrections.