Abnormal Color Vision

Factual Questions
1

Hello Dopers,

So a few weeks ago I went to get my eyes checked out (first time since I had a bottle rocket go off in my face about 18 years ago). My vision is good, I could read all the lines. I told the doctor I suspected having color deficient vision. She showed me a few random Ishihara plates – I failed miserably on some of them just as I expected (I can’t read this shirt either ). So she gave me a 16 little color samples to sort – something that was a bit challenging but I got it 100% correctly. According to my doctor, the 16 hue test trumps Ishihara from diagnosis standpoint (which I think at this point she was assuming I faked :dubious: ), and if I wanted a more definitive answer I should contact the UC Berkeley School of Optometry since they apparently administer the 100 hue test.

Now, I don’t think I’ll have the time to pursue the 100 hue test anytime soon, but I am full of questions. I know I have some sort of color deficiency because I can’t read some of the Ishihara plates that others can. Reading up on all the types of color deficiency none of them really fit. I do have issues with classification of certain colors – a lot of colors people refer to as dark green, purple or violet are down right navy blue to me, but then a lot of lighter purples I would call pinks. I have a friend who is an artist with severe red-green color deficiency and strangely he can see some plates I don’t, yet I can always spot his mistakes when he draws green people or makes deep pink sea.

So what is this I have? Psychological? Simply very mild case of deuteranomaly? Some weird neural vision problem?

Now, note I am not seeking medical advice, just pointers towards what else I can read on the subject (Trust that I’ve read quite a bit about deuteranomaly, protanomaly and tritanomaly accessible by google).

Thanks and best regards,

Groman

2

Like you, I can do sort tests just fine but I flunk Ishihara tests.

There are at least three sorts of anomalous trichromacies and you probably have one of them. It may or may not be dueteranomaly. In fact, I’m inclined to think it’s not, as I have deuteranomalous trichromacy and it’s greens I have problems with, not purples. But I am not an eye doctor nor am I qualified to diagnosis any of this stuff.

3

Here in the US, “average” vision is 20/20, meaning (IIRC) that the patient can see at 20 feet what one with average vision can see at 20 feet.

In metric countries, what do they use?

4

I’m assuming you meant to post this as a separate thread, but in metric countries they use 6/6.

5

Dioptres. Expressed in negative numbers for myopia, and positive numbers for hyperopia.

6

Dioptres are used in the US as well – that’s basically your prescription strength. The visual acuity measurement based on a Snellen chart or similar is measured as 20/x in US and 6/x in metric countries (although the number doesn’t tend to be as widely used).

7

Yes I did. Sorry. :smack: