Indirect ophthalmoscopes: evaluation for potential hazard

The optical radiation emitted from eight indirect ophthalmoscopes was measured. The levels were compared with the threshold limit values (TLVs) published by the American Conference of Governmental Industrial Hygienists. Many tested instruments were found to emit unnecessarily high levels ofultraviolet and infrared radiation in addition to visible light. The levels of optical radiation emitted from most of the ophthalmoscopes were below the applicable TLVs. Nevertheless, suitable blocking filters can reduce the emission of ultraviolet and infrared radiation. Use of the ophthalmoscopes at the lowest possible power setting and the shortest possible exposure time would further minimize patient exposure.