THE PHOTO-OPHTHALMIC THRESHOLD FOR THE RABBIT

A forced transpiration arc source was used to produce high intensity ultraviolet. Using argon gas, the source produced a spectrum from 180 nm to 2.5 μ. Calibration and monitoring techniques are described. The different UV wavebands were obtained using a nickel-sulfate, cobalt-sulfate liquid filter cell and a B & L 500 mm grating monochromator. The photokeratitis thresholds obtained for rabbits were consistently lower than published values. Predictions are made for keratitis thresholds for man in outer space.