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Article
July 1934

LAMP FOR DETERMINATION AND MEASUREMENT OF THE PREFERRED INTENSITY OF LIGHT FOR READING AND FOR OTHER WORK

Author Affiliations

BALTIMORE
From the Research Laboratory of Physiological Optics, Wilmer Ophthalmological Institute, Johns Hopkins Medical School.

Arch Ophthalmol. 1934;12(1):45-59. doi:10.1001/archopht.1934.00830140053005
Abstract

Two important aspects of clear seeing are clearness of imaging and powers of discrimination of the retina. An increase of intensity of light over a suitable range renders important service in relation to both of these functions: 1. By causing a decrease in the size of the pupil it increases the clearness of the image. This effect is especially marked when there are defects in refraction, even in case of small residual defects. 2. By an increase in the sensation difference between the object and the background the retina's power to discriminate details in the image is strongly intensified. Under the higher intensities of light details which would be missed completely under low intensities are discriminated in spite of the blurring of the image. 3. There is also a possible effect on the function of space discrimination, over and above the effect on the discrimination of difference in brightness. It

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