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Article
August 1939

INSTRUMENTS AND TECHNICS FOR THE CLINICAL TESTING OF LIGHT SENSE: II. CONTROL OF FIXATION IN THE DARK-ADAPTED EYE

Author Affiliations

BALTIMORE
From the Wilmer Ophthalmological Institute of the Johns Hopkins University and Hospital.

Arch Ophthalmol. 1939;22(2):228-232. doi:10.1001/archopht.1939.00860080072005
Abstract

It has been known for many years that the region of highest sensitivity in the dark-adapted eye is not at the fovea. This fact was mentioned by Arago1 in 1858, who pointed out that faint lights could be better seen with eccentric than with foveal fixation. The experiments of Breuer and Pertz, reported in 1897 by von Kries,2 showed that the relative insensitivity of the fovea in dark adaptation was far more marked than previous studies had indicated, probably because of inadequate control of fixation in these investigations. Breuer and Pertz made quantitative measurements of sensitivity in central and paracentral regions of the retina with white, blue, yellow and red light. The defect in sensitivity at the fovea was most apparent with blue light, less so with white light and least with yellow light. The sensitivity for red light, however, was slightly greater at the fovea than in

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