Alert! Red-green color blindness affects you, even if you don't have the affliction. Indeed, it might even cost you your life.
This is the most common form of color blindness, affecting white males (1 in 12) much more than females (1 in 200) and also more than other ethnic groups.
One in 12 might sound like a small percentage. Besides, "Why should I worry about it if I am not red-green color blind myself?"
Consider the following: If there is a red stop sign in your neighborhood and it is up against a green background (such as a big bush), every 12th car with a white male at the wheel approaching that intersection might not stop fast enough to keep from T-boning your vehicle - because the driver didn't see the sign.
Now, if the intersection is a busy one, that might amount to five to 10 such vehicles per hour that have the potential to run that stop sign - simply because the drivers don't see it.
The same goes for red traffic lights against a sky that has any hints of green in it. Also, some pale green traffic lights often look white, like other street lights at night, not giving the red-green color blind driver sufficient notice that he is coming upon a traffic signal and needs to be ready to react in case it turns red.
Another example is that, as elders might recall, police cars used to have a single red light on the roof. In contrast, modern squad cars have a beam of flashing blue and multi-colored lights that can't be missed by any kind of color blindness.
Red-green blindness does not mean that one totally can't see the colors red and green. The problem enters in when something red is embedded in a green background.
As a red-green-blindness-afflicted male, I know I have pulled brown pants out of my closet when I thought they were a dull shade of green. A poorly lighted environment like a closet makes these mix-ups even more likely to occur.
Autumn offers another example: Imagine you are riding down the interstate and your wife says, "Look at that beautiful red tree on the mountainside." You say, "What red tree?" because you can't see it against the green mountainside that has yet to change colors.
Then she says, "Can't you see it, right below that cell phone tower about halfway up the mountain?" With those directions, and after dodging five 18-wheelers, you finally notice a tree that looks different from the others. It might even look reddish, but not likely as red as your wife is seeing it.
It seems that anything that involves safety (e.g., stop signs, traffic lights) or need for easy identification (e.g., clothing at night, athletic gear, bicycles) should take into consideration the prevalence of red-green blindness in the population.
Perhaps it is time for blue stop signs.
Dr. Tom Dorsel of Hilton Head Island is a clinical-sport psychologist, musician and author of "GOLF: The Mental Game." Dorsel.com