Lens transmission of blue (say <450 or <500 nm) declines with age - looks vaguely like 2% per year ages 20 to 60.[1] Thus reduced blue-yellow contrast perception in elderly. I don't know of any age-related change in red perception... perhaps those colors were off?

[1] "Fundamental Chromaticity Diagram with Physiological Axes - Part 1" (I'm unclear on CIE copyright, so no link, sorry), section 5.6.