Eye safety implications of repeatedly exposing human subjects to near-infrared radiation were explored. Of particular interest was the infrared radiation emitted by the GaAs diode source of an eye tracking device. The reported safety analysis was considered inadequate in that it was based on short exposure durations, one-time accidental exposures, and/or laser sources. Measurements made in our laboratory of the device's output were related to recent retinal damage threshold data obtained from a GaAs diode. A decision was made to attach a stop to the eye tracker's infrared source to limit the radiation output to a value less than 10% of the critical threshold for retinal damage.
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