Abstract: Scotopic relative spectral luminous efficiency functions have been determinedwith brightness matching method at 8.8×10~(-4)(cd)/m~2. There was a dim redfixation point on the upper edge of a visual field which had a diameter subtending20°at the eye, and was divided vertically into two equal parts, one was thestandard, and the other illuminated with various comparison lights. Two agegroups of subjects were used, one below 30 and the other above 30 years,including 13 and 11 normal vision subjects respectively. 14 points were selectedfor measurement in wavelength ranging from 420 to 640 nm. The results indicated: 1) The average maximum spectral sensitivity of the subjects equals to 515nm. It is slightly higher than that of CIE V′_λ which occurs at about 507 nm 2) The comparison between two age groups shows that V′_λ values decreasein the short wave side of spectrum with the increase of age.

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