The study of dark adaptation is a study of a phase of retinal function, and if one accepts the von Kries theory it is specifically an evaluation of rod efficiency. In a previous paper I reported the results of the tests of dark adaptation obtained in a study of 1,008 eyes1 and in another paper I presented a chart on which such findings may be plotted to enable one to compare the results more easily.2
Almost simultaneously with the beginning of dark adaptation there is a regeneration of the visual purple. Either some failure of this regeneration or a disease of the deeper structure of the retina or choroid may be the principal cause of pathologic dark adaptation. That the retina is richly supplied with vitamin A was shown by Yudkin and his collaborators3 in experiments on animals in which healthy retinal tissue was
FELDMAN JB. DARK ADAPTATION AS A CLINICAL TEST: FURTHER STUDIES. Arch Ophthalmol. 1937;17(4):648–661. doi:10.1001/archopht.1937.00850040082003
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