Flicker-photometric electroretinogram estimates of L:M cone photoreceptor ratio in men with photopigment spectra derived from genetics. J Opt Soc Am A Opt Image Sci Vis 2000 Mar;17(3):499-509
Date
03/09/2000Pubmed ID
10708031DOI
10.1364/josaa.17.000499Scopus ID
2-s2.0-0034146364 (requires institutional sign-in at Scopus site) 75 CitationsAbstract
Relative proportions of long-wavelength-sensitive (L) to middle-wavelength-sensitive (M) cones were estimated by use of the flicker-photometric electroretinogram (ERG). It has been demonstrated that a major source of error in estimates of cone proportions from spectral luminosity functions is the known variation in the lambda(max) of the photopigments [Vision Res. 38, 1961 (1998)]. To correct for these errors, estimates of cone proportions were derived by use of individualized L-cone spectral sensitivity curves deduced from photopigment gene sequences from each subject. For some individuals this correction made a large difference in the estimated cone proportions compared with the value obtained when a fixed standard L cone was assumed. The largest discrepancy occurred in a man estimated to have 62% L cones (L:M ratio 1.6:1) when a standard L pigment was assumed but a value of 80% L cones (L:M ratio 4:1) when his individualized L-cone spectrum was used. From repeated measurements made with the ERG, it was determined that individual estimates of the relative L-to-M cone contributions, expressed as %L cones, are usually reliable within approximately 2%. The average L:M ratio for 15 male subjects was estimated at 2:1 (67% L cones). Previously, a large range of individual variability was reported for L:M ratios obtained from photometry. An unresolved issue concerns how much of the range might be attributed to error. Here efforts have been taken to markedly reduce measurement error. Nonetheless, a large range of individual differences persists. Estimated L:M ratios for individuals ranged from 0.6:1 to 12:1 (40% L to 92% L).
Author List
Carroll J, McMahon C, Neitz M, Neitz JAuthor
Joseph J. Carroll PhD Director, Professor in the Ophthalmology and Visual Sciences department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AdolescentAdult
Color Vision Defects
Electroretinography
Humans
Male
Middle Aged
Photometry
Reference Values
Retinal Cone Photoreceptor Cells
Retinal Pigments