Blue light often causes discomfort glare, but it is unclear which visual pigments are the main contributing factors. Thus, we conducted an experiment to clarify the effects of two visual pigments, S-cones and melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs), by applying a silent substitution method for keeping the stimulations of L and M cones intact in foveal and peripheral vision. The color temperatures of the stimuli were 2700 K and 8000 K, and the luminance value was 1000 cd/m 2 . The background luminance was set to 5.0 cd/m 2 to create photopic conditions. Participants were exposed to the discomfort glare of the two stimuli sequentially and evaluated them using pairwise comparisons. The results showed that stimulation of ipRGCs significantly increases the discomfort glare in peripheral vision whereas the stimulation of S-cones does not, indicating that ipRGCs play a crucial role in the occurrence of discomfort glare caused by blue light.

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LED lighting sources have become widely used in various illumination settings. The purpose of our study is to clarify the effect of luminance level of LED light sources on the visibility of a moving ball. The light was falling on the observers' fovea and 5 luminance levels from 1 ＊ 10 4 to 30 ＊ 10 4 cd/m 2 were prepared. The ball size was 0.16 or 0.25 deg in visual angle. Observers pursued a falling ball in front of the light source, then responded by a two-alternative forced choice (2 AFC) method whether they could detect the ball or not. In addition, observers responded whether they could see the falling ball in whole or partially on the light source, and the apparent size of the ball if observers could detect a ball. The results showed that the probabilities of disappearance increase with luminance levels, and that the probability of disappearance for smaller balls is higher. Balls more frequently appeared partially and smaller with increasing luminance levels. We derived psychometric equations for the probability of the ball-disappearance phenomena as a function of luminance of light source, suggesting that the luminance threshold is around 30 ＊ 10 4 cd/m 2 .KEYWORDS：visibility，disability glare，moving object，luminance，light source

The repor しaddresses the action factors of tl ユe generaUamps calculated by mea 皿 s of the quantification meth 〔 》 dS for cir(］ adian rhythm ． The general larnps were 重 he store − bought 46 LED and 12fluorescent lamps． 皿 亘 e ranges ofthe correlated color tempe 【 atUres and the illuminances of lamps were about 2700 − 7300K and 10〔 ト500 b【． The quant血 cation methods were DIN V503 1−100 model ， Rea ' s proposal model ， Takahashi ' s proposa1 mode 旦 and Enezi ' s pK) posal mode1 ． As a result ， it was fo d 血 at 血e correlated color temperatUres and the illuminances from the larnps have influence on the action factors compared wi 血 kinds ef lamps， 皿 ris resUlt suggested the actien factors between 血e general LED lamps and 血e eXisteCl lamps were approximately − same as long as the correlated color temperatures and the illuminances between the旦 amps were similar ．

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