Quantitation of glaucomatous visual field defects with the Mark II Friedmann analyzer

To evaluate the ability of the Friedmann visual field analyzer to determine visual threshold and the depth of visual field defects, we correlated the visual threshold determined kinetically (Goldmann perimeter) with the static threshold (Friedmann analyzer) in various parts of the central field. We found the following: the Friedmann working threshold correlated linearly with the height of the hill of vision represented by the position of the kinetic isopters of the Goldmann perimeter; the static visual threshold (Friedmann) at a particular location, whether normal or abnormal, was linearly related to the kinetic visual threshold (Goldmann) at that location; and the depth of all visual field defects was essentially the same with both instruments. Thus, the Friedmann analyzer accurately quantitated the central visual field in both the normal and abnormal regions, and may be advantageous for following the progress of early glaucomatous defects. For other patients, however, its usefulness may be limited, because defects outside 25 degrees cannot be documented, the visual field examination may be lengthy and inefficient when quantitating large defects of irregular depth, and the maximal quantitation of depth with the Friedmann analyzer is 2.0 log units less than with the Goldmann perimeter near fixation (but there is progressively less difference for defects further from fixation).