Analysis of the deformation of the useful visual field: a comment on Rantanen (2003)

In the study of variables which may affect peripheral visual perception are several ways of assessing deterioration of this perception. One is evaluation of deformation of the useful visual field. Two techniques of analysis have been considered, by calculation of deformation indices, as proposed by Rantanen in 2003 and by carrying out an elliptical interpolation from the location within the visual field of signals perceived by a subject. This latter means, proposed by Rogé in 2002, enables description of whole field with the aid of two parameters. Comparison of the two techniques clarifies their advantages and disadvantages.