Name: 色覚異常の原因は？ (What Causes Color Blindness?)
Uploaded: 2021-01-14T06:56:29.000Z
Duration: 3 min 46 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

It’s a fun playground question, Is my red like your red? Well if you’re colorblind,

様態の副詞

your red is probably a lot like your green.

Being colorblind not as rare as you’d think. Around 7%–10% of men have some form of what

is commonly called red-green color blindness.

In colorblind people, 75% have trouble with green, while only 20%

It’s not like those colors don’t exist for them. Most ‘colorblind’ people can

actually see these colors when they’re bright, but if they’re dull or muted in some way,

they started to get a little hard to tell apart.

Most men get the gene from their mother’s father. It’s a genetic mutation on the X

chromosome, which means if men get that copy of that gene, they will express it, or experience

it. Whereas most women have two XX chromosomes, so sometimes one x will have the mutation

and the other will be just fine and kind of overrides the mutation.

To understand what exactly this mutation is doing, let’s take a closer look at the eye.

The back of your eyes have a lining filled with photoreceptors. Which means cells that

can sense light. Across the animal kingdom there’s quite a few kinds of these cells.

But humans have only two. Rods and cones. While rods help us see in low light situations,

they see the world in mostly black and white. Cones on the other hand, help us see a rainbow.

Three different kinds of cones, each absorb different wavelengths of light. Short, long

Basically when one of the genes get mutated, one or more of these cones don’t work right.

The most common form of color blindness, red-green, occurs when medium wavelength sensing cones

don’t develop properly. This is called Dichromacy. Monochromacy occurs when two or more of the

light sense cones can’t work, inducing an almost total color blindness.

Less severe is "anomalous trichromacy". Where the cones work.. kind of. They’re anomalous,

or different in some way. So some people might have trouble distinguishing between shades

of colors. A rare condition, achromatopsia, is the inability to see any color. They literally

On the other end of the spectrum, some people see MORE colors. Tetrachromacy occurs when

someone, almost always a woman, has a fourth type of cone cell. But not a single case was

The idea that some people might have a fourth cone was put forward in the late 1940s by

Dutch scientist HL de Vries. After studying color blindness in men, he thought that maybe

their daughters might carry the mutation too. Since the mutation is carried on the x chromosome,

that means women with the gene would have three normal cones, but ALSO the mutation.

But after searching and searching scientists couldn’t find a single person with this

condition until 2010. It seems that it takes training to unlock the powers of this fourth

cone. Concetta Antico works as an artist and sees shades we can’t even imagine. She sees

pink in moonlight and red in green leaves. But it’s not all sunshine and roses, she

says going to the supermarket is like “a trash pile of colour”. While genetics aren’t

all that rare, maybe up to 12% of women have the gene, it takes training to really see

all the possibilities, like becoming a painter.

So no, you probably aren’t a tetrachromat and no, that alone doesn’t prove or do anything

really. Sorry to burst your bubble. On the other hand though, you can still lose your

sense of color even if you don’t have the gene due to eye, nerve, or brain damage, or

even exposure to certain chemicals. Or some people’s ability to distinguish colors can

fade over time. The cones just get worn out. Over half of people 85 or older have some

trouble seeing colors. according to a study published in Optometry and Vision Science.

As you get older the optical media within the lens fades and yellows. So some greens

So enjoy that color while you can kid. It won’t last forever. So excuse me, i’m

going to go take photos of a sunset or something.

Speaking of colors, have you ever wondered if seeing red makes you angry? Check out this

video to find out how colors affect your mood!