Having now had both cataracts removed and new plastic lenses inserted into my eyes, I have found that I had been looking at the world through a somewhat yellow cast [not, I should point out, the same as "a jaundiced eye"!] for the past few years. I have had to turn down the brightness on the computer monitor as the pale blue lower case script was post-op almost fading into the background. It could be that this observation could explain some folk's recollection of what 'Big Four' colours were as I certainly wasn't aware that a yellow cast crept up on your vision as you aged.