STUDY OF THE CORNEAL FLAVOPROTEINS AFTER TOPICAL HYPOXIA USING REDOX FLUOROMETRY

Purpose The cornea is frequently associated to hypoxia, whether during residence in the heights or more often when wearing contact lenses. T o evaluate the corneal modifications induced by hypoxia at an infracli nical stage, we have used redox fluorometry that enables to study in v ivo the metabolic response of the cells while measuring the fluorescen ce of the flavoproteins (FAD) of the corneal cells. Methods The variat ions of the corneal fluorescence were studied in 12 healthy subjects, before and after a topically-induced 5-minute corneal hypoxia, submitt ing 2 eyes to a prehumidified flow of nitrogen 100%. The results were compared to those found in the same subjects eu exposure under the sam e conditions to an ambiant air flow (N-2 = 69%; O-2 = 21%). The measur ements of the corneal fluorescence were carried out With the fluoropho tometre Flurotron Master FM2. Results The authors did not find any sta tistically significant difference in the corneal fluorescence between the right and the left eyes of these 12 subjects, whether under normal conditions, under hypoxia, or under air flow (wilcoxon T-test, Friedm an lest). Conclusion As there are no significant results, these author s suggest that the chosen exposure time although sufficient in vitro t o induce a modification of the fluorecence of the cellular flavoprotei ns, may be too ''short'' in vivo. The use of complementary filters wit h the FM2 system would yield move information. The study of these resu lts led the authors to broaden their search whether by looking for con ditions for general hypoxia (hypobarric box) or by increasing local hy poxia (contact lenses).