Keratitis solaris is caused by ultraviolet radiation in the range 200-
320 nm. The threshold dose for keratitis solaris is 40 J/m(2) for shor
t-term exposure. We measured the emission spectra of 22 sunbeds in the
range 250-500 nm with a high-resolution double monochromator and calc
ulated the exposure times for the threshold dose of keratitis solaris.
Depending on the type of lamp used, the exposure times ranged from 90
s to 3.5 h. Lamps with short exposure times for keratitis solaris can
induce keratitis solaris if protective goggles are not used (e.g., to
achieve a uniform tan of the eye area) and if the eyes are opened bri
efly several times, perhaps, to look at a watch. Generally, sunbed use
rs have no way of ascertaining the lamp type or its emission spectrum
and of determining the exposure time for the threshold dose of keratit
is solaris.