All ETDs from UAB

Advisory Committee Chair

Michael S Loop

Advisory Committee Members

Tim Gawne

Adam Gordon

Lei Liu

Lawrence Sincich

Document Type


Date of Award


Degree Name by School

Doctor of Philosophy (PhD) School of Optometry


Color discrimination varies between individuals even in the absence of a congenital color vision defect. Attempts to explain this variation have shown no link to macular pigment optical density, L:M cone ratios, non-verbal IQ, or female carriers of color vision deficiencies. This study examined individuals’ relative luminance and color-opponent systems sensitivity to their Farnsworth-Munsell 100-Hue (FM-100) color discrimination ability. Thirty normal color vision subjects performed FM-100 and increment threshold testing for white, blue, green and red on a 150 cd/m2 white background. White increment thresholds were compared to colored increment thresholds to produce a luminance to color-opponent system sensitivity ratio (L/C ratio). The sum of these ratios produced a total L/C ratio for each subject. Total error scores (TES) on FM-100 testing were compared to a total L/C ratio to determine a linear regression correlation. Our key finding indicates that variation in normal human color discrimination shows a reliable correlation to individual differences in relative luminance and color-opponent systems sensitivities (r= -0.44, p = 0.016). As total L/C ratio increased, subject total error score decreased. In keeping with the Helmholtz-Kohlrausch Effect, colored increment L/C values were high for blue and red followed by green, thus demonstrating this effect at threshold. We presume this difference in systems sensitivity improves color discrimination by enhancing color saturation.

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