TESTING VISUAL FIELDS BY FLICKER FUSION

THE CRITICAL rate at which a flickering light of decreasing frequency is first perceived to flicker is the one test of visual function in which the light-adapted eye is more sensitive at the periphery of the retina than at its center. Previous investigators have agreed that flicker fusion fields are sensitive and "typical" in neurological lesions. Phillips1(1933) reported two cases of pituitary tumor in which flicker fusion fields proved superior to standard fields. He used a mechanical sector disk method, testing flicker fusion frequency in 17 areas of each field. Riddell2(1936) using a similar device and procedure, reported one case in which standard fields showed only a small temporal slant, while flicker fusion fields showed complete hemianopsia. Werner3(1942) found pronounced lowering of flicker fusion frequency in 41 patients with various disorders of the central nervous system. Hylkema4(1942) found that flicker fusion frequency