ASSESSMENT OF VISUAL CONTRAST SENSITIVITY IN HYPERBARIC-OXYGEN

Hyperbaric oxygen therapy is used in ophthalmology in ischemic patholo gies of the anterior and posterior segments. Our experiment was done o n a healthy group of volunteers aged between 10 and 50 yr. We examined the subject's vision before and after acute HBO exposure (60 min at 2 .5 atm abs with pure oxygen) to verify whether vasoconstriction induce d by hyperoxemia can influence eyesight. We measured the psychophysica l determination of the threshold contrast according to Maione-Maffei's zebra test. The results demonstrated that contrast sensitivity is sig nificantly improved for almost all the studied frequencies in normal s ubjects after acute HBO exposure. We hypothesize that the visual syste m has a reserve which is activated by an improvement of retinal oxygen ation.