ABSTRACT
The effect of acute air-hyperbarism (maximal 520 kPa), normobaric low and high FIO2 levels (minimal 0.1, maximal 1.0) and hyperbaric oxygen (HBO2) on the red-green sensitivity ratio (rgSR) and on color discrimination for foveal vision were studied. Effects were quantified by measuring the red-green flicker (16 Hz) fusion point for normals with the Oscar tester (Am J Optom Physiol Opt 1983; 60:892-901). Color discrimination was examined with the Lanthony's Desaturated 15 Hue test After 15-20 min of exposure rgSR is enhanced 4% (relatively increased red sensitivity) by normobaric acute hypoxia, and reduced 4% by normobaric hyperoxia (FIO2 = 1.0), but HBO2 gives a smaller reduction, and air-hyperbarism (FIO2 = 0.21) has no effect. Hypercapnia (increased FICO2), normobaric hypoxia (reduced FIO2), and HBO2 increase the duration of the Lanthony's test about 20-40%, but the number of errors were practically unchanged. The reduced effect during HBO2 upon rgSR is attributed to an opposing effect of hypercapnia. The absence of an effect during air-hyperbarism is probably due to a suppression by nitrogen of the effect of high PO2. In general, during moderate air-hyperbarism and HBO2 color vision seems to be normal, but evaluation of the colored scene is probably less stable and slightly slower.
