On the threshold radiant exposure for keratitis solaris.

Marked inflammation of the cornea (keratitis solaris) is often observed after exposure to strong solar radiation, especially in high altitudes and snow-covered terrain. Using the action spectrum and the solar spectrum, the radiant exposure causing keratitis solaris was calculated for a horizontal surface. The parameters selected were altitude, season, ozone content and albedo. The radiant exposure of the eye increases approximately 16-fold, comparing terrain without snow-cover and terrain with snow-cover. Radiant exposures in clinically observed cases of keratitis solaris were calculated to range from 1200 to 5600 Jm-2. A discussion on these figures with regard to threshold doses shows a significant difference between long-term exposure to solar radiation and short-term exposure to artificial sources.