Method |
Assumption |
Study |
Mean ratio (L/M cones) |
Range of ratios |
| Photopic luminosity function | Compares the relative numbers of L- and M-cones required to fit an indivdual or standard flicker photometric function. | De Vries (1947) | -- |
0.59 - 4.0 |
| Vos & Walraven (1971) | 2.0 |
-- |
||
| Walraven (1974) | 2.0 |
-- |
||
| Smith & Pokorny (1975) | 1.6 |
-- |
||
| Smith & Pokorny (1989) | -- |
0.50 - 10.0 |
||
| Spectral acuity | Compares visual acuities for heterochromatic gratings. | Brindley (1954) | << 1.0 |
-- |
| Kelly (1973) | << 1.0 |
-- |
||
| Fundal reflectometry | Compares the optical densities of the L- and M-cone pigments at 535 nm, following selective bleaches. | Rushton & Baker (1964) | 1.0 |
0.33 - 3.00 |
| Weber fractions | Compares the Weber fractions for Stiles' red and green p-mechanisms. | Vos & Walraven (1971) | 1.64 |
-- |
| Spectral sensitivity functions | Compares the relative heights of the spectral sensitivities of the cone primaries. | Walraven (1974) | 2.0 |
-- |
| Point source detection | Relates the steepness of the psychometric functions to the cone numbers contributing to detection. | Cicerone & Nerger (1989) | 2.07 |
1.46 - 2.36 |
| Vimal et al. (1989) | 2.8 |
1.6 - 4.0 |
||
| Cicerone et al. (1994) | 2.0 |
1.3 - 2.5 |
||
| Human ERG | Compares the amplitudes of the isolated L- and M-cone ERG responses. | Shapley & Brodie (1993) | >>1.0 |
-- |
Compiled by Ted Sharpe.
Brindley, G.S. (1954). The order of coincidence required for visual threshold. Proceedings of the Physical Society, London B 67, 673-676.
Cicerone, C.M. & Nerger, J.L. (1989). The relative numbers of long-wavelength-sensitive to middle-wavelength-sensitive cones in the human fovea centralis. Vision Research 29, 115-128.
Cicerone, C.M., Gowdy, P.D. & Otake, S. (1994). Composition and arrangement of the cone mosaic in the living human eye. Investigative Ophthalmology & Visual Science 35 (supplement), 1571.
De Vries, H.L. (1947). The heredity of the relative numbers of red and green receptors in the human eye. Genetica 24, 199-212.
Kelly (1974). Spatio-temporal frequency characteristics of color-vision mechanisms. Journal of Physiology, London, 228, 55.
Rushton, W.A.H. & Baker, H.D. (1964). Red/green sensitivity in normal vision. Vision Research 4, 75-85.
Shapley, R.M. & Brodie, S. (1993). Responses of human ERG to rapid color exchange: implications for M/L cone ration. Investigative Ophthalmology & Visual Science 34 (supplement), 911.
Smith, V.C. & Pokorny, J. (1975). Spectral sensitivity of the foveal cone photopigments between 400 and 500 nm. Vision Research 15, 161-171.
Smith, V.C. & Pokorny, J. (1989). In: Proceedings of the AIC Wyszecki & Stiles Memorial Symposium on Colour Vision Models.
Vimal, R.L., Pokorny, J., Smith, V.C. & Shevell, S.K. (1989). Foveal cone thresholds. Vision Research 29, 61-78.
Vos, J.J. & Walraven, P.L. (1971). On the derivation of the foveal receptor primaries. Vision Research 11, 799-818.
Walraven, P.L. (1974). A closer look at the tritanopic convergence point. Vision Research 14, 1339-1343.