Thermal effect of visible light and infra-red radiation (i.r.-A, i.r.-B and i.r.-C) on the eye: a study of infra-red cataract based on a model.

Exposure to intense optical radiation leads to the development of infra-red (i.r.) cataracts in the workplace. To investigate the importance of the wavelength of optical radiation in i.r. cataract formation, the temperature rises induced in the eye by monochromatic optical radiation (visible light and i.r.) were calculated on the basis of a mathematical model. It is shown that, in accordance with Goldmann's theory when visible light or i.r.-A (780 nm < or = lambda < or = 1400 nm) is incident on the eye, the radiation is absorbed by the iris and converted into heat which is then conducted to the lens and induces cataracts. When i.r.-B (1400 nm < lambda < or = 3000 nm) or i.r.-C (3000 nm < or = lambda < or = 1 mm) is incident on the eye, on the other hand, it is absorbed by the cornea and converted into heat which is then conducted to the lens and induces cataracts. It is suggested that i.r. cataracts are induced by i.r.-B or i.r.-C in the workplace.