Development and Use of Gradient Isopters in Computerized Perimetry

Abstract

Usually, the presentation of visual field results is done by print-outs of the original data or by greyscale charts obtained by interpolation algorithms. Less often, data are used to calculate the three-dimensional ‘hill of vision’. A new method is presented to create isopters of a new kind, based on the evaluation of original Octopus data by image analysis. These ‘gradient isopters’ contain more information than those generally used, being of different width according to the actual slope of the retinal sensitivity in the area tested. Thus, gradient isopters may be mixed electronically with the corresponding fundus picture, the results giving quantitative information of a ‘two step fundus perimetry’ based on the use of both optimal fundus photography and perimetry. Problems still arise from the different kind of the concerned projections.