[Redox fluorometry study of corneal flavoproteins following hypoxia. Preliminary results]

The cornea is frequently associated to hypoxia, whether during residence in the heights or more often when wearing contact lenses. To evaluate the corneal modifications induced by hypoxia at an infraclinical stage, we have used redox fluorometry that enables to study in vivo the metabolic response of the cells while measuring the fluorescence of the flavoproteins (FAD) of the corneal cells.

The variations of the corneal fluorescence were studied in 12 healthy subjects, before and after a topically-induced 5-minute corneal hypoxia, submitting 2 eyes to a prehumidified flow of nitrogen 100%. The results were compared to those found in the same subjects after exposure under the same conditions to an ambiant air flow (N2 = 69%; O2 = 21%). The measurements of the corneal fluorescence were carried out with the fluorophotometre Flurotron Master FM2.

The authors did not find any statistically 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, Friedman test).

As there are no significant results, these authors suggest that the chosen exposure time, although sufficient in vitro to induce a modification of the fluorecence of the cellular flavoproteins, may be too "short" in vivo. The use of complementary filters with the FM2 system would yield more information. The study of these results led the authors to broaden their search whether by looking for conditions for general hypoxia (hypobarric box) or by increasing local hypoxia (contact lenses).