Effects of known variations in photopigments on L/M cone ratios estimated from luminous efficiency functions

Michelle L. Bieber, James M. Kraft, John S Werner

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The extent to which known variations in photopigment λ(max) and optical density may affect cone ratios estimated from the spectral luminous efficiency function (LEF) was examined. LEFs were generated using L- and M-cone fundamentals, one of which had been shifted in λ(max) (± 1, 2, 4 or 6 nm) or varied in peak optical density (increased or decreased by 10, 25 or 50%). A curve-fitting program was then used to estimate the L/M cone ratios for the generated LEFs assuming standard L- and M-cone fundamentals. These modeling exercises indicate that L/M cone ratios estimated from LEFs are highly correlated with long-wave sensitivity and with known variations in L-cone λ(max). Variations in M-cone λ(max) and photopigment optical density for both cone types are also correlated with L/M cone ratios, but have much less impact on the estimated ratios.

Original languageEnglish (US)
Pages (from-to)1961-1966
Number of pages6
JournalVision Research
Issue number13
StatePublished - Jun 1998
Externally publishedYes


  • Heterochromatic flicker photometry
  • L/M cone ratio
  • Luminous efficiency

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems

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