Spectral sensitivity for extrafoveal discomfort glare

Previously published evidence suggests that the discomfort glare response to bright lights has greater short-wavelength spectral sensitivity than implied by the photopic luminous efficiency function, V(). The present paper summarizes a series of experiments to characterize spectral sensitivity for discomfort glare from nearly monochromatic light sources presented in the near extrafovea (5 degrees and 10 degrees off-axis). The results are consistent with increased participation in the discomfort glare response from short-wavelength cones and greater short-wavelength sensitivity as eccentricity increases. From the results an empirical family of luminous efficiency functions, VDG(), for discomfort glare, is derived. Such data could have implications for specifications of roadway lighting, vehicle headlamps or other light sources that might contribute to discomfort glare.