Tabulated at 0.1, 1 or 5 nm steps, these functions are the mean macular pigment optical densities for a 2 deg of visual diameter field. The 0.1 and 1 nm functions were obtained by the interpolation of the 5 nm functions using a cubic spline. Stockman, Sharpe and Fach (1999) adopted this macular density spectrum, which is based on measurements provided by Bone (personal communication), because its use in analyzing S-cone spectral sensitivity data yielded plausible estimates of the S-cone photopigment optical density change from the central to the peripheral retina. In contrast, the Vos (1972) and Wyszecki & Stiles (1967; 1982) templates yielded estimates of the optical density change that were implausibly high (see below). The differences between the templates are mainly at very short wavelengths, where the reliability of the Vos, and Wyszecki & Stiles templates is questionable. The density spectrum also appears in Fig. 3 of Bone, Landrum & Cains (1992), but only for wavelengths above 420 nm. Further details about its derivation can be found there. Briefly, the template was derived as follows: Lutein and zeaxanthin were mixed in the same ratio as found in the foveal region and incorporated into phospholipid membranes (in the form of liposomes). The absorbance spectrum of such liposome suspensions is grossly distorted by scattering, so a carotenoid-free liposome suspension has to be placed in the spectrophotometer reference cell. Bone, Landrum & Cains (1992) argue that this membrane environment more or less duplicates that of the carotenoids in the macula.
Bone, R. A., Landrum, J. T., & Cains, A. (1992). Optical density spectra of the macular pigment in vivo and in vitro. Vision Research, 32, 105-110.
Stockman, A., Sharpe, L. T., & Fach, C. C. (1999). The spectral sensitivity of the human short-wavelength cones. Vision Research, 39, 2901-2927.
Vos, J. J. (1972). Literature review of human macular absorption in the visible and its consequences for the cone receptor primaries. Soesterberg, The Netherlands: Netherlands Organization for applied scientific research, Institute for Perception.
Wyszecki, G., & Stiles, W. S. (1967). Color Science: concepts and methods, quantitative data and formulae. (1st ed.). New York: Wiley.
Wyszecki, G., & Stiles, W. S. (1982a). Color Science: concepts and methods, quantitative data and formulae. (2nd ed.). New York: Wiley.