I was mentioning how much I thought it was a good idea and one of my Qatari friends said it wasn't that useful since there was little difference between the lights so it made it very difficult to tell. That made me pause for a second and I asked, "you don't see much of a difference between the red and green light?”. He said no, they looked similar. That's when it dawned on me.
I asked him, "Do you have red/green colorblindness?"
I'm sure most of you are aware that red/green colorblindness is pretty common in men, affecting anywhere from 1 in 10 to about 1 in 25 depending on ancestry. It's genetic, and is due to a defect on the X chromosome, which means a man inherits it from his mother. For a woman to suffer from colorblindness both parents would have to have the gene and pass it on so it is a lot rarer in women (because women are XX and the defect is recessive only if both X chromosomes have the defect will a woman get colorblindness, men are XY so only one copy of the defective X-chromosome is needed). I've known a few people who have had red/green colorblindness, which is why I think I spotted the issue right away with my friend.
He said he suspected he might be but had never been tested for it. So once we got back to the office I loaded up an Ishihara test from the internet (if you've never done one before I suggest you click on the link). The test shows you coloured circles and in the circles is a number, but if you have certain types of colorblindness you won't see the number and instead see a circle where everything is the same color. It's a pretty simple and ingenious way to test for colorblindness.
So my friend tried it and sure enough he couldn't see a number in most of the circles. He thought it was quite strange when I would tell him, “no, there is a number
So another Qatari told us that many men in his family are also colorblind (he wasn't) and that got me thinking if colorblindness was more prevalent in Qatar than in most other places in the world. The overall population of Gulf Arabs was never very large and they tend to be closely knit, usually marrying within their tribe, which would mean genetic conditions could be more common. Unfortunately a quick search of health websites had no mention of it, and government websites had nothing either. I would be curious though if anyone has any information on this please let me know.
My friend went home and had other members of his family took the Ishihara test. It turns out that one of his brothers is also colorblind, not too surprising since I think it's a 50-50 chance for any of his brothers.
To cheer him up a little I mentioned that there is at least one advantage to red/green colorblindness. A study indicated that certain types of camouflage were less effective against colorblind people since the camouflage was designed for fooling full-color vision. I've even heard that some militaries try to utilize this by having some colorblind individuals in units in the hopes that they might be able to see through any camouflage the enemy will be using. Couldn't find much about it on the Internet but the U.S. Army does accept colorblind individuals, though what jobs you can select are more limited. I don't think you can be a pilot though.