DESPITE DIFFERENT WALL COLORS, VERTICAL SCOTOPIC ILLUMINANCE PREDICTSPUPIL SIZE

Previously we have determined, with a full field of view, the relative contributions of scotopic and photopic luminance to pupil size at lig ht levels typical of building interiors. Those studies were carried ou t in a white room with uniform reflectance, and with the viewed surfac es having an approximately uniform luminance distribution. To enhance the usefulness of the past results to lighting practice, we have const ructed a ''simulated office'' where the viewed walls can have one of f our very different colors, with quite different luminance distribution s. This allows examination of interaction effects between wall spectra l reflectivity and light source spectral distribution. In the present study pupil sizes were obtained while subjects were viewing a very sma ll screen television. A remote pupillometer was used, allowing subject s to sit in a comfortable chair without the inconvenience of chin rest s or head gear Seventeen subjects between the ages of 27 and 47 years were studied using illumination provided by conventional lamps, either a WW or a daylight lamp. Pupil size variation was predicted by the va lue of the scotopic vertical illuminance at the eye. Even though the W W lamps are 50 per cent more efficacious than daylight light lamps in terms of photopic lumens per watt, daylight lamps can be as much as tw ice as efficacious in eliciting pupil size.