Although I"ve never had good 'blue' vision at all ~ a shortage of blue receptors I suppose, as long as I had my rods intact they made up for most of the color deficiency (the rods overlap the blue cones reception frequencies).
After some serious eye surgery I lost a great deal of my rods in my right eye. That means I no longer have blue vision in much of my right eye, and that means I can't see yellow either!
What you saw 20 years ago may well not have anything to with how you see it today. Add in cataracts, scarification, retinal repairs, and about 753298 different possibilities, and it's amazing we can see anything at all!
Hmmmm. Could be, I mean I just got bifocals a few years ago. If there are any truth to the contrail stories, actually I’m ambivalent on that one, I wonder if that is a factor too.
AMEN!
(Where we not warned, as youths, that we’d go BLIND!!!!)