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Calliopenjo
01-25-2009, 03:36 AM
This is about monochromatic vision. What I would like to know is would the person be able to read a book? Would they be able to see objects close up? Would they need special glasses such as reading glasses?

alleycat
01-25-2009, 03:44 AM
Seems to me like it would be like watching a black and white TV.

veinglory
01-25-2009, 03:56 AM
Not necessarily. If the color sensing cones don't work acuity would probably be effected.

HoraceJames
01-25-2009, 03:59 AM
Check out Oliver Sacks' book, Island of the Colorblind. He's a brilliant writer as well as a neurologist.

http://www.oliversacks.com/island.htm

There are several different types of colorblindness, congenital, due to brain injury, etc.

alleycat
01-25-2009, 04:01 AM
Not necessarily. If the color sensing cones don't work acuity would probably be effected.
Good point. And if I remember correctly, the rods are much more sensitive, only not to color.

semilargeintestine
01-25-2009, 04:25 AM
Monochromatic vision is actually part of a condition known as achromatopsia, which can refer to several different diseases. Typically though, it refers to an autosomal recessive congenital color vision disorder, as well as the inability to perceive color or achieve satisfactory visual acuity at high light levels such as daylight. It is quite uncommon, and occurs in 1 of about every 33,000 people. Complete achromatopsia, in which no color is able to be seen, is even more uncommon and is associated with a number of additional visual aberrations; included is--you guessed it--decreased visual acuity to about 20/200, which is pretty bad. I had 20/200 vision before getting LASIK, and I could barely make out the big E on the eye exam chart.

So, if your question is would they be able to read without glasses, the answer would most likely be no, especially since complete achromatopsia is associated with nystagmus and hemeralopia, which are involuntary eye movements and the ability to see clearly in daylight.

Barb D
01-25-2009, 04:41 AM
In Lois Lowry's The Giver everybody sees the world in black and white. The MC begins to see color, has no idea what it is, and it freaks him out.

semilargeintestine
01-25-2009, 04:51 AM
Yeah, well realism isn't really high on her priority list. It depends on what you want. I think a story about an achromat trying to cope with life could be pretty good. There are plenty of real hardships those people go through just trying to get dressed in the morning, let alone hold down a normal job and make any kind of commute.

FinbarReilly
01-25-2009, 12:16 PM
So, if your question is would they be able to read without glasses, the answer would most likely be no, especially since complete achromatopsia is associated with nystagmus and hemeralopia, which are involuntary eye movements and the ability to see clearly in daylight.
But I thought you said that complete achromatopsia is even more uncommon...meaning it was rarer.

So, based on that, merely being to not perceive color would not necessarily limit the ability to read...

FR

Shweta
01-25-2009, 01:14 PM
1. Foveal vision

Good point. And if I remember correctly, the rods are much more sensitive, only not to color.

They are. But the fovea, which is the part of the retina that's responsible for high-resolution focal vision (it's where the image you're focusing on lands on the retina, and while we don't realize it, we see everything else extremely blurrily), is mostly cones. So if the cones aren't there, or aren't working, or the brain isn't processing their input, you're left with very few of the cells involved in focal vision. Something like trying to read a screen when only one pixel in 50 is actually lighting up. (But: More on this in part 3 below, because you can have complete colorblindness with some working cones)

So you'd end up with, as semilargeintestine says --


--decreased visual acuity to about 20/200, which is pretty bad. I had 20/200 vision before getting LASIK, and I could barely make out the big E on the eye exam chart.

2. how bad is bad vision?

I have 20/200 vision or worse in one eye, and ditto, can barely make out the big E -- but I can use that eye to read, especially if the text is big, so long as it's really close to my eye.

Since my issue is a problem with the way the lens is focusing the image on the retina, rather than on the number of working rods 'n cones, I"m not sure if this translates to the original question. It's possible that my 20/200 vision still gives me better acuity at close range than that of someone with complete achromatopsia (though in that case I'm not sure what it means for their vision to be 20/200). And there's still this:


So, if your question is would they be able to read without glasses, the answer would most likely be no, especially since complete achromatopsia is associated with nystagmus and hemeralopia, which are involuntary eye movements and the ability to see clearly in daylight.

Also, there's a difference between someone being able to learn to read and someone being able to read once they've learned. You know how messy/blurred writing is really hard for kids to read, but easier for adults? Or hard to read in a foreign language but easier in your own? It's because we're actively pattern-matching. Once we are fluent readers, we have a good idea of what the pattern could be, andcan figure out the best fit; so we can understand a more distorted signal than we can when learning (this is true for processing spoken speech too -- non-native speakers often don't understand mumbled speech that native speakers can, even if they know the words; they need things enunciated so they can recognize those words).

So if someone has this problem from birth, they might not be able to learn to read unless there are major steps taken to help them. And if the problem is bcause of an accident or illness, they'll have other side effects.

3. Different types of Monochromacy
However...
The rare condition we're talking about, rare as it is, seems to be the most common version of total colorblindness; there are other causes and they have other effects.

You can be unable to see color because of cerebral damage (brain damage). I am guessing that this would have other effects, and the precise issues would depend on the details of the cerebral damage. You might also have trouble with visual imagery (imagining visual stimuli) if you had this problem, depending on where the damage was.

And achromatopsia (http://en.wikipedia.org/wiki/Rod_monochromacy), which we've been talking about so far, is the term most normally used for "rod monochromacy", the situation where you don't have any working cone cells. But you can also have "cone monochromacy", (normally called monochromacy (http://en.wikipedia.org/wiki/Cone_monochromacy)), which means you have rods and one type of cone in the retina. One type of cone isn't enough to let you see color, but it is enough to help your visual acuity somewhat, and to let you see patterns at normal daylight levels.

For the most part (the parts I know) the wikipedia articles I've linked to are pretty good. However, I think they confuse some of the effects of cone monochromacy with those of rod monochromacy. I'm not sure when you get the nystagmus(involuntary eye movements), whether it's with one of them or both. Cone monochromacy lets you see better than rod monochromacy in normal daylight; however, if cone monochromacy leaves you with nystagmus too, it's still not very much better than rod monochromacy.

psaluka
01-25-2009, 02:57 PM
Wow, you got some great answers...Do you want the character to be strictly monochromatic or would a less severe condition be okay? As far as visual function goes, there are lots of folks who are more mildly "color blind" (like red/green) with 20/20 vision at distance and near. (20/20 just means you can see at twenty feet what "normal" people see at twenty feet. 20/200 means what the "normal" eye sees at 200 feet, you can only see at 20 feet)

As far as reading glasses go...Basically, unless you're dealing with a severe condition like achromatopsia or a pathology like macular degeneration, reading vision without glasses is good for a lot of people (I will qualify in the next paragraph) until sometime in their forties. (And actually, to be honest, there are some things that glasses just don't fix--like stroke/foveal damage)

There are exceptions. Anyone who is super far-sighted (better vision naturally at distance) or really, really super near-sighted (better at close until you get into minus double digits--see post above, #2) will likely need glasses all the time to get the best vision possible (and be most comfortable-you wouldn't want to read at your nose all the time). So will anyone with anything worse than a mild astigmatism (the front of the eye is shaped like an american football instead of a basketball). Some people also have accomodative disorders (just a fancy way of saying they can't focus up close for one reason or another).

As far as the whole reading glasses for those of us over 45...well, not sure how old your character is. If it's something you want more info on you can look up "presbyopia" or pm me.

I agree with the post above, these severe congential conditions come in bunches. Someone born with them would have a much harder time learning to read.

2Wheels
01-25-2009, 08:22 PM
I think it depends on how close to reality's rules you want to adhere. I have a WIP about a woman who suffers a head injury and ends up with a bizarre atypical case of colour blindness (that has all the neurologists and opthamlogists baffled). She then starts to have remote viewing experiences in full colour.

One of her biggest issues is eating--she has to do it with her eyes closed, because the colour distortions of the food make her nauseous.

Some of it then, could be up to you.

Chase
01-25-2009, 10:06 PM
I have red-green color blindness. Blue is the only color I'm sure of, but then purple and aquamarine both appear blue.

Up into my forties, my eyes were better than 20/20, but now I only need glasses to read.

Some problems:

1. All colors on traffic lights looked the same before blue was added to green due to many people having the red-green problem. Even so, in the U.S., red is always on top, green at the bottom, and I can see the light, just not distinquish its color.

2. I have to stop at the single caution or stop light at remote intersections, as yellow caution looks the same as red stop.

3. Directions like "The gold house with the lime roof and ruby trim" are lost on me. I have to know the numbers.

4. I ask people I trust to help me coordinate clothing, and then I put things that go together on one hanger.

5. I match socks by material and design.

Some perks:

1. Camouflage doesn't work on me. When hunting, I see animal hides as different textures long before other hunters see them.

2. I don't get "tired" of the paint on walls.

3. My couch always goes with the rest of my furniture.

4. What's the big deal about separating colors before washing?

5. After my girlfriend sees what I'm wearing, we often don't need to go out for dinner after all, and we get to stay home and order pizza delivered.

Claudia Gray
01-26-2009, 01:36 AM
My brother is almost wholly color-blind -- it isn't all gray, but it's essentially gray and tan. He is able to read and see just fine, though as Chase points out, some cues we take for granted don't work for him. But he makes sure his wife picks out and matches all his clothes!

Calliopenjo
01-26-2009, 02:03 AM
Thanks guys. :Hug2:

Kazel
01-27-2009, 01:20 AM
I didn't read all the posts carefully, but figured I could throw in my two sense. My good friend has blue-cone monochromacy, so he can see colors, he just can't see the all the colors, or normally the correct colors. What color things appear to be change based on the lighting. Contrast is important for him to be able to see, so if he wanted to be able to see the lines on lined paper, he needed to have paper with thick black lines. He never wore glasses because he had a bad habit of losing things and the glasses were extremely expensive. He could read, he just held the paper right up to the end of his nose. He cannot see well enough to drive, likely even with corrective glasses. The doctors tell him he shouldn't do things like rock climbing ect because his depth perception is off and it could be dangerous, but he does anyway and never had any issues. Being friends with him, it was pretty easy to forget that he had vision issues, except when talking about color or watching him read. His vision is bad enough that he is legally blind, but he get around fine.
For awhile he had glasses he wore to help him see that had red lenses.
If you have any specific questions, PM me and I may be able to get him to answer them for you :-)