Cold light sources. Are they really cold?

Two light sources used in laparoscopy, both in the photo mode, proved capable of burning a hole in a standard paper surgical drape in less than five seconds. The relationship between power (in watts) and dial settings is not linear. Both of these sources have a maximum power density of 5.6 w/cm2, which far exceeds the 1.8 w/cm2 power density of the other light sources tested. Today, with the demand for increased illumination for photodocumentation , the physician must be cognizant of its potential hazards. Light sources will vary according to the type of source--tungsten, halogen or mercury arc. Each increase in wattage output will transmit a greater cable power density. Equipment should be checked for its potential to produce burns in routine use and, if defective, should be replaced.