color vision deficiency

[princealbertofb]

I see color slightly differently between one eye and the other… I've never had it checked so I don't really understand "why" it is… I just know that if I close one eye and then the other in rapid succession, the colors vibrance between one eye and the other is slightly different. It could just as well be psychological (right brain / left brain) as physiological, I suppose. As a painter I often used it to help me evaluate color tones I was matching.

It's probably something to do with how your eye receives the waves of colour and the way your brain processes them.

[meridannight]

It's probably something to do with how your eye receives the waves of colour and the way your brain processes them.

anything affecting just one eye is not something the brain processing contributes to. it's wholly in the eye.

i'm gonna explain this.

our eyes have a different neural wiring than the rest of the body. while in motor control the right side of the brain controls the left side of the body and vice versa, this isn't the case with eyes. the right side of the brain does not control the left eye, and the left side of the brain does not control the right eye.

it is this way: your field of vision in each eye is split into the left side and the right side (left hemifield of the retina and the right hemifield of the retina).

--left hemiretina in the LEFT eye (temporal) is sent to the LEFT side of the brain.
--right hemiretina in the LEFT eye (nasal) is sent to toe RIGHT side of the brain.
--left hemiretina in the RIGHT eye (nasal) is sent to the LEFT side of the brain.
--right hemiretina in the RIGHT eye (temporal) is sent to the RIGHT side of the brain.


this adds up to:
--LEFT field of vision in both eyes is sent to the RIGHT cerebral hemisphere.
--RIGHT field of vision in both eyes is sent to the LEFT cerebral hemisphere.

(NB. the image is also inverted in the vertical plane).

here's a simplified diagram i drew:




both eyes send projections to both sides of the brain. it is easy to see from this that if there is a problem in the brain or the neural pathways along the way after the optic chiasm, it would affect both eyes in the same way. not just one eye. if it was in the brain processing [MENTION=20947]MikeW[/MENTION] would have altered color vision in both eyes.

[princealbertofb]

@meridannight, thanks for your explanations but I don't think it makes what I said untrue.... Whichever part of the brain processes what that eye sees, the outcome is still that Mike seems to see things differently in one eye and the other. The brain (whichever part) is clearly able to make a distinction in hues.

[meridannight]

The brain (whichever part) is clearly able to make a distinction in hues.

actually, it is not quite so. because the difference is felt only when switching between right-eye-only and left-eye-only. when both eyes are open at the same time [MENTION=20947]MikeW[/MENTION] should see a uniform color distribution. the two eyes see different hues, but when both eyes are open the brain doesn't detect the difference. these two hues get mixed (or maybe the one from the dominant eye overrides the other, i don't quite know) due to convergent inputs to the brain. ergo, it is not in the brain at all. (the same brain areas process information from one field of vision from both eyes. if it was in the brain both eyes would thus be affected. not to mention, the fact that the same brain area is capable of seeing two different hues at different times when closing the relevant eye, already proves it is in the eye). i can't put it any simpler past recommending reading a book on neuroscience to understand the logic behind this.

PS. i have pictures to illustrate what i'm talking about (from a book on neuroscience i'm reading) and i'll post them later in the day when i have a bit more time.

[princealbertofb]

Just to remind you that what I said was the eyes probably perceive the color waves differently. You haven't, so far proved me wrong, only said that the brain does some uniformisation of the colours when both eyes are open (or maybe one eye gives the dominant information to the brain). Let's say that both eyes watch the same object, which ought to have the same colour, when each eye sees the object with different colours then it must be the way each eye perceives the color waves... (they "receive" them differently and they are "decoded" differently, presumably).

[matty7]

I used to have a terrible time in the chat room with colours that people used to type comments with - sometimes I could tell they had typed something but just could not see it - bright red was really hard to see for me

[meridannight]

Just to remind you that what I said was the eyes probably perceive the color waves differently. You haven't, so far proved me wrong, only said that the brain does some uniformisation of the colours when both eyes are open (or maybe one eye gives the dominant information to the brain). Let's say that both eyes watch the same object, which ought to have the same colour, when each eye sees the object with different colours then it must be the way each eye perceives the color waves... (they "receive" them differently and they are "decoded" differently, presumably).

that's what i've been saying all along. i only argued against it being in the brain.

they're not decoded differently. it's in the pigment protein that's expressed in the cone cell. there are three different types of cone cells and each expresses a different protein that reacts most optimally to a certain wavelength of light. it's lack of a type of cone cell, or expression of a pigment protein slightly varied from normal that's accountable for color vision anomalies/deficiencies.

[princealbertofb]

Thanks, grazie, [MENTION=21405]meridannight[/MENTION].