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March 1957

Temporal Aspects of the Human Electroretinogram: A Study of the Implicit Time-Amplitude Relationship of the B-Wave

Author Affiliations

Bethesda, Md.
Ophthalmology Branch, National Institute of Neurological Diseases and Blindness, National Institutes of Health, Public Health Service, U. S. Department of Health, Education, and Welfare.

AMA Arch Ophthalmol. 1957;57(3):386-392. doi:10.1001/archopht.1957.00930050398010

During the past decade intensive work by psychologists, physiologists, and ophthalmologists has shown that the human electroretinogram (ERG) is a result of two basic forms of response—scotopic and photopic. The differentiation of these two components has been achieved through the study of the ERG in normal, color-blind, and night-blind subjects, under different states of adaptation, with stimuli of varying wavelengths and intensities.

The scotopic and photopic components of the human ERG are similar in that each consists of a negative deflection succeeded by a positive one. There is a difference, however, in their temporal characteristics, the photopic response following a more rapid course than the scotopic response. Furthermore, the photopic positive wave (x-wave) maintains a constant latency and implicit time,* regardless of the experimental condiregardless of the experimental conditions, tions, whereas the scotopic positive wave (b-wave) shows a marked variation.

It is the purpose of this investigation to study the

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