Effects of hypoxia and hyperoxia on the human standing potential.

We report that the human standing potential, measured by the EOG, rises slowly when oxygen saturation is lowered to near 80% by breathing a controlled oxygen-nitrogen mixture. The standing potential falls abruptly by 20-30% of its amplitude when the oxygen saturation returns to 100%. These changes can be generated reproducibly, with minimal discomfort, under conditions that could be adopted for clinical use. Animal experimental studies by Linsenmeier and Steinberg suggest that this hypoxia-hyperoxia response may be a delayed response to potassium concentration changes in the subretinal space. Since there is no requirement for light and no involvement of the Müller cells, the hypoxia-hyperoxia response may be more specific for pigment epithelial pathology than the c-wave.