Abstract The corneal epithelium has been shown1 to have an active metabolism that requires more oxygen than is provided by the aqueous humor and the limbal capillaries.2 Under normal conditions, the cornea utilizes atmospheric oxygen.3,4 Experimental limitation of this source of oxygen in the rabbit cornea has resulted in turbidity, swelling, and increased content of lactic acid and water.5,6 These same effects, produced in human subjects, rabbits, and guinea pigs by wearing contact lenses,6-8 are attributed to the interruption of the aerobic metabolism of the active epithelial cells upon which both epithelium and stroma appear dependent for energy for carbohydrate breakdown.9 A recently developed method for measuring lactic acid and oxidized pyridine nucleotides in the same extracts of tissue from the individual cornea10 has been used in this case to study the metabolism of the corneal epithelium and stroma of rabbits wearing contact lenses References 1. Pirie, A., and van Heyningen, R.: Biochemistry of the Eye , Springfield, Ill., Charles C Thomas, Publisher, 1956, pp. 158-167. 2. Langham, M.: Utilization of Oxygen by the Component Layers of the Living Cornea , J. Physiol. (Lond.) 117:461, 1952. 3. de Roetth, A.: Respiration of the Cornea , Arch. Ophthal. 44:666, 1950.Crossref 4. Heald, K., and Langham, M. E.: Permeability of the Cornea and the Blood-Aqueous Barrier to Oxygen , Brit. J. Ophthal. 40:705, 1956.Crossref 5. Langham, M.: Respiration of the Cornea , J. Physiol. (Lond.) 115:65P, 1951. 6. Langham, M. E., and Taylor, I. S.: Factors Affecting the Hydration of the Cornea in the Excised Eye and the Living Cornea , Brit. J. Ophthal. 40:321, 1956.Crossref 7. Smelser, G. K.: Relation of Factors Involved in Maintenance of Optical Properties of Cornea to Contact-Lens Wear , A.M.A. Arch. Ophthal. 47:328, 1952.Crossref 8. Smelser, G. K., and Chen, D. K.: Physiological Changes in Cornea Induced by Contact Lenses , A.M.A. Arch. Ophthal. 53:676, 1955.Crossref 9. Herrmann, H.: Direct Metabolic Interactions Between Animal Cells , Science 132:529, 1960.Crossref 10. Morley, N. H., and Toth, A.: Oxidized Pyridine Nucleotides and Lactic Acid in the Corneal Tissue of Rabbits , Canad. J. Biochem. 39: 477, 1961.Crossref 11. Herrmann, H., and Hickman, F. H.: Exploratory Studies on Corneal Metabolism , Bull. Johns Hopkins Hosp. 82:225, 1948. 12. Smelser, G. K., and Ozanics, V.: Structural Changes in Corneas of Guinea Pigs After Wearing Contact Lenses , Arch. Ophthal. 49:335, 1953.Crossref 13. Kuhlman, R. E., and Resnik, R. A.: The Oxidation of C14-Labeled Glucose and Lactate by the Rabbit Cornea , Arch. Biochem. 85:29, 1959.Crossref 14. Kinoshita, J. H.: The Stimulation of the Phosphogluconate Oxidation Pathway by Pyruvate in Bovine Corneal Epithelium , J. Biol. Chem. 228: 247, 1957.
Archives of Ophthalmology – American Medical Association
Published: Sep 1, 1961