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Abstract

Research in neurobiology has identified a new ocular photoreceptor (melanopsin or ipRGC) which mediates a variety of light-based, non-visual effects on human physiology. One way to isolate the stimulation of ipRGCs is the silent substitution technique. We have built a Maxwellian view device capable of 85% ipRGCs contrast excitation with a large FOV (52o). Four modulated LED light sources, illuminate a diffusing sphere, which exit aperture is imaged into the pupil of the eye. A camera with a 900 nm illumination capture the pupil. Without luminance changes (510±2 lm/m2), we increased ipRGC excitation from low to high level on three subjects. We observed a pupil constriction increasing with the ipRGC contrast. This suggests that we excite melanopsin silently. However, further experiments with electrophysiological and pupil recording needs to be done to completely validate our silent substitution device.

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