Lasers were used to directly scan the retina in the early 80s1. These devices are called scanning laser ophthalmoscopes (SLO) and make it possible to obtain large field fundus images with high contrast and resolution yet with a lower illumination than conventional imaging systems. It was shown that these scanners could also stimulate the visual process and interest grew in using this technology for “virtual reality” displays2. A simple equation is developed to express permissible power output of a VRD based upon the ANSI Z136.1-1993. An equation is also proposed for permissible powers for multi-wavelength displays.

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Richard
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