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(λ). 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° and 10° 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, V DG(λ), 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.