Spectral sensitivity curves were determined at mesopic luminance levels, 0.1 and 0.01 ft-L, for a 2° field viewed foveally and parafoveally. These data are compared with similar curves for a 10° field, centrally fixated, whose area encompasses the smaller areas studied individually. The results show that, at 0.1 ft-L, differences between the 2° and 10° fields are similar to those between the CIE 2° and 10° photopic curves; furthermore the large field data can be predicted from the 2° data. At 0.01 ft-L however the spectral sensitivity is different from both CIE photopic and scotopic values at all positions and summation within the large field is complex.
Jo ANN S. KINNEY, "Effect of Field Size and Position on Mesopic Spectral Sensitivity," J. Opt. Soc. Am. 54, 671-677 (1964)