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September 1959

Visual Acuity in Normal and Amblyopic Patients Under Reduced Illumination: II. The Visual Acuity at Various Levels of Illumination

Author Affiliations

Iowa City
From the Department of Ophthalmology, College of Medicine, State University of Iowa.

AMA Arch Ophthalmol. 1959;62(3):396-399. doi:10.1001/archopht.1959.04220030052008

In the first part of this study1 we reported on the influence of a neutral-density filter on the visual acuity of patients with normal eyes, with strabismic amblyopia, and with organic retinal damage. The present, second, part deals with the visual acuity at different levels of illumination of three similar groups of patients.

Material and Procedure  Ten eyes with central fixation and strabismic amblyopia, ranging in visual acuity from 5/6 to 5/15 with single optotypes; ten eyes with amblyopia due to pathologic fundus lesions, such as diabetic retinopathy and macular edema, and ten eyes with normal visual acuity were examined.Prior to the test the patients were kept for 10 minutes in a completely darkened room. Single optotypes (black letter "E" on white ground) were then presented at 5 meters distance. The optotypes were shown to the patients in an evenly illuminated box. The illumination was controlled