New developments in the application of the multimeridional apparent frontoparallel plane.

This study is a sequel to a previous publication that introduced the multimeridional apparent frontoparallel plane (MAFPP) as a method of measuring aniseikonia. As the term implies, apparent frontoparallel plane (AFPP) responses are obtained not only in the horizontal meridian, but also in oblique meridians. Since the introductory publication, the method has been applied extensively for measuring aniseikonia and has been found to be reliable, accurate, and easily adapted to clinical purposes. This study presents a more detailed and comprehensive account of the underlying theory than did the introductory report. It clarifies some problems inherent in the method originally presented and describes a simplified and improved procedure for measuring aniseikonia. It describes the application of the theory to a number of specific clinical situations. Finally, it is suggested that the method has a much broader application than the clinical measurement of aniseikonia.