THE RELATION BETWEEN DARK ADAPTATION AND THE LEVEL OF VITAMIN A IN THE BLOOD

Abstract

Dark adaptation of 37 normal persons revealed no sex difference. The mean vit. A plasma level for the [female][female] was 14% lower than that for the [male][male], whereas the mean carotenoid levels were the same. 67 simultaneous dark adaptation and plasma vit. A and carotenoid measurements on 14 normal persons, 18 persons with cirrhosis of the liver, and 7 persons with various other chronic diseases showed no significant correlations within the cirrhotic and normal groups, separately considered. When all of the normal and abnormal subjects were grouped together a degree of correlation between the dark adaptation measurements and vit. A values became apparent. This was interpreted as arising from differences peculiar to the several diagnostic groups rather than from a causal relation between the level of vit. A in the blood and dark adaptation.