Original article

Scand J Work Environ Health 1979;5(3):280-285    pdf


Temperature changes in contact lenses in connection with radiation from infrared heaters

by Lövsund P, Nilsson SEG, Öberg PÅ

A number of reports have appeared over the past few years with warnings about the wearing of contact lenses in certain trades involving exposure to arc flash. In view of these reports and in light of knowledge on the marked absorption by contact lenses, within the infrared (IR) region, temperature changes were measured in soft contact lenses under radiation from IR heaters used, for example, in the motor industry for drying paint. The lenses were tested while free-hanging and when applied to rabbit eyes. Great increases in temperature were noted with one of the heaters at a distance corresponding to "safe." During 10 min of exposure the temperature of a free-hanging lens rose from 21 to 59°C, whereas the temperature in the surrounding air increased only from 26 to 30°C. The final temperature of the lens was thus 29°C higher than that of the air. In lenses applied to rabbit eyes the temperature rose within only 0.5, 1.0, and 1.5 min from approximately 33°C to about 44, 49, and 51°C, respectively; the air temperature rose from 25 to only 28°C. In other words, the ultimate lens temperature was 23°C higher than the ambient air temperature. In the rabbit experiments most of the lenses dried out completely. There would thus seem to be considerable risk of contact lenses drying and becoming adherent to and damaging the corneal surface among workers exposed to powerful radiation from IR radiators (IR heaters), unless they use efficient eye protectors. IR heaters appear to be associated with greater hazards than arc flashes, since there is no warning from powerful visible light and because they are capable of causing a very rapid increase in temperature.

This article refers to the following texts of the Journal: 1979;5(3):271-279  1979;5(3):262-270
The following article refers to this text: 1979;5(3):271-279