Colour vision test: annually, or once per lifetime? (and colour vision discussion)

Clipperstorch wrote:

Can you even lose CV after you had it for the first part of your life? I mean in a way that doesn’t require consultation with an AME anyway, like when you smack really hard?

Yes you can: AMD, or diabetic retinonopathy are very common ones. More rare ones are some infections/inflammations of the visual nerves, but also cataracts and glaucomas can lead to impaired color perception.

In most of these cases you should consult your AME anyways – and then the AMC to part Med would imply there is a clinical indication that your CV test should be repeated

I do both Transport Canada and FAA medicals together so I don’t know 100% which is responsible, but I am shown the book of numbers on various backgrounds at every medical (usually at high speed ) … I assume that is the Ishihara/Isihara or whatever. I believe that it’s in the Transport Canada AME “curriculum”. I queried the doctor once during a medical, and he said that it is not unusual for CV to degrade slightly with “advancing age”. Other than for perhaps the original medical, I don’t think the test is applied as a 100% pass or fail, but rather to give an indication of degradation and depending on how many slides are missed might result in further investigation. It could indicate other eye issues.

I’ve heard that in Japanese as of today there is no verbal differentiation between blue and green.

True and not true. In old Japanese there was only one word, aoi, for both. But in modern Japanese that means just blue, and there is a kind of borrowed word, midori, for green. It does lead to some oddities tough – like the city of Aomori, which in modern Japanese literally means “blue forest”. Also the “green” colour of traffic lights is called “aoi”, and as a result Japanese traffic light green is as close to blue as it can get while still being plausibly green.

(Colours in Japanese are a little strange. It only has “proper” color adjectives for white, black, red and blue/green. But it can describe colours just as well as any other language, using a variety of “borrowed” words originally with other meanings. Brown, for example, is cha-iro, literally “tea coloured”).

chflyer wrote:

I don’t think the test is applied as a 100% pass or fail, but rather

In EASA-land Ishihara is used as a binary test – the complete test has about 25 pictures in somewhat ascending level of difficulty and it is required that you can read the first 15 or so (number is written in the AMC to part MED i just don’t remember exactly) without any error.
Obviously that is on paper and one can imagine that reality might be a bit different if you struggle with one of those 15 …

So far, in Switzerland, it has been done at every medical.

Malibuflyer wrote:

The similarity between green and blue is more a cultural and a psychological one – different people have different mental models of the colors blue and green and therefor refer to the same color with a different verbal identification.
This goes as far as the Ancient Greek not even having a word in their language to differentiate between blue and green. Same with many ancient languages with the notable exception of the ancient Egypt who were some of the few early cultures who had synthetic blue colors. I’ve heard that in Japanese as of today there is no verbal differentiation between blue and green.
That doesn’t mean that all of these people do not see a difference, but they simply have other names (like “dark green” or “sea green”) that describe shades of green.

That’s some info Not sure I agree though (I’m very sure I don’t agree to be hones ) There are lots of different tests for color blindness or color perception. The thing is, I don’t come from a culture where green and blue isn’t differentiated. When I look at something and see blue, the rest of my family laughs and say, no this is green. And of course I have to agree It has a name, it’s called tritan color blindness, and comes with age, sometimes a symptom of glaucoma. It’s also called blue-yellow colorblindness (for some odd reason). I regularly check my eyes. So far nothing wrong, so I guess it’s just age related (damage from UV light over time or some other stuff).

It’s a deep philosophical debate as to how different people see colours, and it will never be completely resolved

Perhaps, but tritan color blindness is very physical, and directly linked to damage receptors. I don’t think anyone is born with tritan color blindness as opposed to red/blue.

Peter wrote:

You can fail the Isihara plates 100% and still see all the colours just fine (that’s a fact, btw).

Yes, but the rules accommodate that possibility. The Isihara plates are really for screening.