RETINAL LIGHT EXPOSURE FROM OPHTHALMOSCOPES, SLIT LAMPS, AND OVERHEAD SURGICAL LAMPS - AN ANALYSIS OF POTENTIAL HAZARDS

  • 1 January 1980
    • journal article
    • research article
    • Vol. 19  (9) , 1009-1015
Abstract
The projected beam radiance of several common ophthalmologic instruments was measured, and the potential hazard to the patient from light exposure was analyzed with reference to safety standards for coherent light. The indirect ophthalmoscopes tested appeared safe under moderate voltage settings, provided exposure was reasonably brief. Slit-lamp biomicroscopy of the fundus merits caution. It produced a retinal irradiance 3 .times.-higher than the indirect ophthalmoscope. Overhead surgical lamps produced a retinal irradiance about 1/3 that of the indirect ophthalmoscope (for clear media and dilated pupil). This was dangerous, since an operation may take long enough to exceed the maximal permissible exposure by several orders of magnitude. Major design changes are indicated for surgical illuminators to extend the safe time to the 40-60 min range.

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