[Informative value of psychophysical examinations aside from conventional white-white perimetry]

In addition to routine light-sense perimetry testing, elementary visual function, i.e., light difference sensitivity, numerous methods and procedures were developed to test more complex psychophysical threshold criteria in glaucoma patients in order to detect functional glaucomatous loss earlier. The various methods differ with respect to the area of the visual field tested (central, perimetric, global or Ganzfeld stimulation) and the psychophysical threshold criteria (spatial and/or temporal transfer, color, complex criteria including form perception, etc.). Two domain proved to be of special interest: examination of the temporal transfer properties (flicker stimulation, motion perception, "motion-defined-form") and testing of the short-wave-length cone system (blue/yellow perimetry). The blue cone system is part of the parvocellular pathway, criteria in the field of temporal transfer may be allocated to the magnocellular pathway. There is histopathological evidence that ganglion cell axons of the magnocellular system are prone to glaucomatous damage in an earlier stage of the disease. There may even be some kind of specific damage. The role of various psychophysical procedures are discussed with reference to data in the literature and own experience with special emphasis on the practical applicability for early diagnosis of functional glaucomatous damage.