interesting color "blindness"

Recently I talked to a friend (male) who said he has a type of color
blindness in which the green is "amped up". He said he sees things as
greener than they are, and, if I remember correctly, sees red rather
poorly.

Sometimes with unfamiliar objects, he cannot determine their correct
color. He said he visited an entomologist who had an exotic
tarantula. My friend was exclaiming over the rich color of the
tarantula's fur, which appeared to him to be a deep forest green.
The entomologist rushed over in surprise and said, no, it's just
plain black.

Anyone know what this type of vision is called?

cheers,
Liz

On Jan 10, 3:03*pm, Liz <fraternobom...@yahoo.com> wrote:
> Recently I talked to a friend (male) who said he has a type of color
> blindness in which the green is "amped up". *He said he sees things as
> greener than they are, and, if I remember correctly, sees red rather
> poorly.

It's called protanopia or "red-blind", one of the two common types of
inherited colour vision defects. The cone pigment that responds most
to red light is defective and red light is not seen. Green is not
amplified, but as red is not seen, in any colour that consists of
mixture of red and green, it will appear more green to your friend
than it does to someone with normal colour vision.

People with colour vision defects will confuse some colours that
appear quite different to the rest of us. Colours such as pink and
light gray, red and dark grey, orange and yellow, purple and blue may
appear to be the same. Brown and black are mixtures of red, yellow
and blue; they may be confused with various shades of green since the
red is not seen, leavng the yellow and blue.


Judy

On Jan 13, 7:12*am, "^_^" <misa...@googlemail.com> wrote:
> On 12 Jan, 21:11, Dr Judy <mpac...@rogers.com> wrote:
>
>
>
>
>
> > On Jan 10, 3:03*pm, Liz <fraternobom...@yahoo.com> wrote:
>
> > > Recently I talked to a friend (male) who said he has a type of color
> > > blindness in which the green is "amped up". *He said he sees thingsas
> > > greener than they are, and, if I remember correctly, sees red rather
> > > poorly.
>
> > It's called protanopia or "red-blind", one of the two common types of
> > inherited colour vision defects. *The cone pigment that responds most
> > to red light is defective and red light is not seen. * Green is not
> > amplified, but as red is not seen, in any colour that consists of
> > mixture of red and green, it will appear more green to your friend
> > than it does to someone with normal colour vision.
>
> > People with colour vision defects will confuse some colours that
> > appear quite different to the rest of us. Colours such as pink and
> > light gray, red and dark grey, orange and yellow, *purple and blue may
> > appear to be the same. *Brown and black are mixtures of red, yellow
> > and blue; they may be confused with various shades of green since the
> > red is not seen, leavng the yellow and blue.
>
> > Judy
>
> Doctor Judy, how do you explain what is described here?

I have never had a patient regard a black letter and believe it to be
coloured. Migraine aura can create various distortions of vision
including shape, size and colour, aura is thought to be due to
alterations in neurotransmitters in the brain.

Judy

On Jan 13, 5:12*am, "^_^" <misa...@googlemail.com> wrote:
> On 12 Jan, 21:11, Dr Judy <mpac...@rogers.com> wrote:
>
>
>
> > On Jan 10, 3:03*pm, Liz <fraternobom...@yahoo.com> wrote:
>
> > > Recently I talked to a friend (male) who said he has a type of color
> > > blindness in which the green is "amped up". *He said he sees thingsas
> > > greener than they are, and, if I remember correctly, sees red rather
> > > poorly.
>
> > It's called protanopia or "red-blind", one of the two common types of
> > inherited colour vision defects. *The cone pigment that responds most
> > to red light is defective and red light is not seen. * Green is not
> > amplified, but as red is not seen, in any colour that consists of
> > mixture of red and green, it will appear more green to your friend
> > than it does to someone with normal colour vision.
>
> > People with colour vision defects will confuse some colours that
> > appear quite different to the rest of us. Colours such as pink and
> > light gray, red and dark grey, orange and yellow, *purple and blue may
> > appear to be the same. *Brown and black are mixtures of red, yellow
> > and blue; they may be confused with various shades of green since the
> > red is not seen, leavng the yellow and blue.
>
> > Judy
>
> Doctor Judy, how do you explain what is described here?
>
> [...] When a patient regards a black letter and believes it to be
> grey,
> yellow, brown, blue, or green, he is suffering from an illusion of
> color. This phenomenon differs from color-blindness. The color-blind
> person is unable to differentiate between different colors, usually
> blue and green, and his inability to do so is constant. The person
> suffering from an illusion of color does not see the false colors
> constantly or uniformly. When he looks at the Snellen test card the
> black letters may appear to him at one time to be grey; but at
> another
> moment they may appear to be a shade of yellow, blue, or brown. Some
> patients always see the black letters red; to others, they appear red
> only occasionally. Although the letters are all of the same color,
> some may see the large letters black and the small ones yellow or
> blue. Usually the large letters are seen darker than the small ones,
> whatever color they appear to be. Often different colors appear in
> the
> same letter, part of it seeming to be black, perhaps, and the rest
> grey or some other color. Spots of black, or of color, may appear on
> the white; and spots of white, or of color, on the black. [...]

It's quite probably unmitigated bullshit.

But ... you have a seemingly unlimited capacity to uncritically absorb
that, so .....

> It's called protanopia or "red-blind", one of the two common types of
> inherited colour vision defects. *The cone pigment that responds most
> to red light is defective and red light is not seen.

At all? Or just poorly?

> in any colour that consists of
> mixture of red and green, it will appear more green to your friend
> than it does to someone with normal colour vision.

Ahhhhhh.

> People with colour vision defects will confuse some colours that
> appear quite different to the rest of us. Colours such as pink and
> light gray, red and dark grey, orange and yellow, *purple and blue may
> appear to be the same.

Yes, now I remember he mentioned this too.

Cool, thanks!

liz

> >*Migraine aura can create various distortions of vision

I've had optical migraines, but they don't look like anything is
changing color. They look like vibrating flashing zigzags.

On Jan 15, 12:11*am, Liz <fraternobom...@yahoo.com> wrote:
> > It's called protanopia or "red-blind", one of the two common types of
> > inherited colour vision defects. *The cone pigment that responds most
> > to red light is defective and red light is not seen.
>
> At all? * Or just poorly?

It depends on the depth of the defect. Some don't see red at all, some
see it poorly.

Judy