RT Journal
A1 HECHT S, MANDELBAUM J
T1 THe relation between vitamin a and dark adaptation
JF Journal of the American Medical Association
JO Journal of the American Medical Association
YR 1939
FD May 13
VO 112
IS 19
SP 1910
OP 1916
DO 10.1001/jama.1939.02800190024006
UL http://dx.doi.org/10.1001/jama.1939.02800190024006
AB I. PURPOSE 
    Night blindness and similar visual disturbances have long been associated with the nutritional state of the body. In recent years this connection has been traced to the vitamin A of the diet1 and has become understandable in terms of the chemical relation between vitamin A and the light-sensitive pigments of the retina.2After the establishment of vitamin A as a factor in the visual cycle, it seemed logical to use the properties of vision for the detection of early stages in vitamin A deprivation. Such tests were made by Edmund and Clemmesen3 with visual intensity discrimination as an index and by Jeans and Zentmire4 with dark adaptation as a criterion. Other investigations5 followed and, though some of this work has been found to be perhaps more enthusiastic than critical,6 it showed that the original idea is probably sound and that under properly