Critical Flicker Frequency, Photochemical Mechanisms, and Perceptual Responses

Introduction  In the past 15 years a great deal of attention has been directed toward the phenomenon of "flicker" as an indicator of retinal sensitivity and pathology. This report will present results with a flickermeasuring device, only slightly modified from that described in 1952.¹ Ophthalmic application of flicker has not always been successful. After a brief review of the literature this paper will direct attention to the meaningfulness of the flicker phenomenon, as shown in its correlation with electroretinography, and demonstrate the need of applying psychometric principles in ophthalmic practice, by referring to laboratory results.Flicker is a purely subjective phenomenon. It refers to the appearance of an alternating light and dark visual stimulus at certain specific rates of alternation. When the visual field, in whole or part, slowly alternates between dark and light, perception will follow the alternation; the dark phase will have the appearance of darkness, and