L, M and L-M hybrid cone photopigments in man: deriving lambda(max) from flicker photometric spectral sensitivities

Using heterochromatic flicker photometry, we have measured the corneal spec tral sensitivities of the X-chromosome-linked photopigments in 40 dichromat s, 37 of whom have a single opsin gene in their tandem array. The photopigm ents encoded by their genes include: the alanine variant of the normal midd le-wavelength sensitive photopigment, M(A180); the alanine and serine varia nts of the normal long-wavelength sensitive photopigment, L(A180) and L(S18 0); four different L-M hybrid or anomalous photopigments, L2M3(A180), L3M4( S180), L4M5(A180) and L4M5(S180); and two variants of the L-cone photopigme nt, encoded by genes with embedded M-cone exon two sequences, L(M2; A180) a nd L(M2; S180). The peak absorbances (lambda(max)) of the underlying photop igment spectra associated with each genotype were estimated by correcting t he corneal spectral sensitivities back to the retinal level, after removing the effects of the macular and lens pigments and fitting a template of fix ed shape to the dilute photopigment spectrum. Details of the genotype-pheno type correlations are summarized elsewhere (Sharpe, L. T., Stockman, A., Ja gle, H., Knau, H., Klausen, G., Reitner, A. et al. (1998). J. Neuroscience, 18, 10053-10069). Here, we present the individual corneal spectral sensiti vities for the first time as well as details and a comparison of three anal yses used to estimate the lambda(max) values, including one in which the le ns and macular pigment densities of each observer were individually measure d. (C) 1999 Elsevier Science Ltd. All rights reserved.