Figure 5. Chromatic sensitivity as a function of age.

Thresholds along the protan (left most), deutan (middle) and tritan line (right most) is plotted as function of age for all 185 observers. A linear regression analysis revealed that the slope for all three sets of thresholds differs significantly from zero: Protan: slope = 0.004 R² = 0.119 p<0.001; Deutan: slope = 0.003 R² = 0.139 p<0.001; Tritan: slope = 0.254 R² = 0.258 p<0.001.