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Physiologic Significance of Relative Concentrations

EDWARD F. PURCELL, M.D.; LEONARD H. LERNER, M.D.; V. EVERETT KINSEY, Ph.D.

AMA Arch Ophthalmol. 1954;51(1):1-6.

	Since this article does not have an abstract, we have provided the first 150 words of the full text PDF and any section headings.

MANY ATTEMPTS have been made to explain how the concentration of ascorbic acid in the aqueous humor is maintained in excess of that in the blood.¹ Three different mechanisms have been proposed: (1) Ascorbic acid is synthesized by the lens *; (2) ascorbic acid is transported across the ciliary epithelial border in the oxidized state (i. e., as dehydroascorbic acid), where it is reduced to ascorbic acid by the lens ; (3) ascorbic acid is selectively concentrated by the ciliary epithelium, whence it diffuses to the posterior chamber.⁷

The chief evidence in support of the theories that associate the lens with the maintenance of relatively high concentrations of ascorbic acid in the aqueous humor is the observation that the concentration of the acid is less than normal when the lens is cataractous or absent. For instance, reduced concentrations of ascorbic acid in the aqueous humor have been observed . . . [Full Text PDF of this Article]

Author Affiliations
DETROIT

From the Department of Ophthalmology of the City of Detroit Receiving Hospital, and the Kresge Eye Institute.

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