Patent ID: 7258438

Claim:
A system for approximating flux density of light on a retina, the system comprising: a housing defining an inside and having an opening allowing light to pass to the inside of the housing; a baffle coupled to the housing, the baffle replicating the facial cutoff function for the light passing to the inside of the housing; a first detector positioned to detect the light inside the housing, the first detector producing a photopic spectral response function of the light inside the housing that approximately replicates a spectral response of foveal cones; a second detector positioned to detect the light inside the housing, the second detector producing a scotopic spectral response function of the light inside the housing that approximately replicates a spectral response of rods in the retina; and a processor coupled to the first and second detectors, the processor being configured to calculate a flux density of the light inside the housing based on the photopic and scotopic spectral response functions.