Figure 6.

Comparison of the model (solid lines) with neural contrast sensitivity functions at six retinal illuminance levels extracted from (A) Figure 5 of Kawara and Ohzu (1977), Figure 5 of Campbell and Green (1965), and Figures 2d and 2g of Coletta and Sharma (1995) and from (B) Figure 5 of Williams (1985) and Figure 5 of Dressler and Rassow (1981). Model curves are for the 20 to 29 age-group; the Campbell and Green (1965) curve is for a 27-year-old. Kawara and Ohzu (1977) and Coletta and Sharma (1995) did not specify ages; the mean age of six subjects from Williams (1985) was 36 years; and Dressler and Rassow (1981) pooled data from six age-group decades. RMS log neural contrast sensitivity differences between the model curves and literature are annotated alongside the curves.