Any eye doctors out there??  With the human eye, can you see color (with cones) without your rods (for B&W)?
956853
sorry, I agree that D is correct. (\nhttp://www.abledata.com/abledata_docs/Night_Vision.htm )\n\nAs perception of white (or any gray levels) is the equal stimulation of all three different photopigments/photoreceptors, you can see all grey levels using your cones only. No mystery about it. If you understand additive color mixing you can use Photoshop to prove this on your computer. Or you can use colored transparencies and a projector. Research additive color mixing if you are not familar with it. So you can have no rods (look up night blindness) and still see black (no stimulation) and white (equal stimulation of all three cones) during the day time using your cones only. So the answer is no, you can not be "black, grey, white blind" , but it doesn't have to do anything with the presence or absence of rods in your eyes. \n\nThough there seems to be a really minor effect of rods on the perceived hue, colors could be somewhat less saturated,and it seems to rely on interaction of nerve cells other than the primary photoreceptor cell. Generally Pubmed or Google Scholar should both allow you to search large databases of science publications which haven't made it into textbooks.
524507
Simple answer:\n\nThe rods and cones in our eyes pick up on the different waves in light. The primary colors of light are:\nGreen\nRed\nBlue\nWith the combination of these different wavelengths of light we can get any of the other colors including yellow.\n\nPigments work different. Whereas the colors we recieve from  TV's and lightbulbs is by the combination or "addition" of wavelengths of light, pigmentation occurs by "subtraction" of light and it also has different primary colors. The primary colors of pigments (any object is seen by pigments whereas a TV's colors works by wavelenths of light rather than pigments) are:\nYellow\nBlue \nRed\nAnd those colors are seen by subtration meaning the light hits the particular object and every color gets absorbed except whatever color get reflected and that is the color we see.\n\nhope this helps.
7427
You take a test at the eye doctor.  Color blind people generally only lack the ability to see certain shades of a color like purple for example.  They wouldn't be able to differnciate between a sheet of blue and a sheet of purple paper.
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photoreceptors. they allow us to be able to see in low light such as moonlight but also in very bright lights. the photoreceptors are devided in to two groups rods and cones.\nrods are for low light\ncones for bright light. \nolder people can damage photo receptors and thats one reason for legal blidness. if you have damage you can not legally drive.
1136736
Rather odd question. I don't know if you could look at yourself or not. Maybe so if you didn't break the optic nerve. I have known of fights were one's eye popped out and it was popped back in. But thank heavens I didn't see it.
130436
First of all little “white” lies are only acceptable to some in the general population.  Many still believe that all lies are contrary to best behavior.  But as an example, I get your point.\nThe association of white with good and black with bad predates recorded history.  This generalization is almost universally true in all cultures.\nThe best possible answer goes back to the time before artificial nocturnal lighting.  Humans are visual creatures.  We tend to rely upon and believe what our visual system records.  The eye itself has two kinds of receptors.  These are called Rods and Cones.  The Rods are more sensitive and give us the shades of gray in “night vision.”  The Cones respond to colors and are more active during the day.  Humans see more clearly and with better spatial acuity during daylight hours.\nWhite is a mixture of colors and is only perceived during the day.  Daylight = Better vision = Good.  At night, when the rods take over:  Night = Poor vision = Bad.\nFor a very detail report on vision, try the site below:
1131053
the retina is the sensory layer of the eye, and it contains two types of sensory cells: rods and cones.  rods are great for seeing in dim light and detecting motion and shapes.  cones require brighter light and enable us to see colors and detail.  you can see a good diagram here: http://www.usm.maine.edu/psy/broida/101/retina.JPG\n\nthe retina is not a uniform mixture of rods and cones.  cones are concentrated at the fovea, which is a thinner layer of cells (in fact it is entirely cones, no messenger cells or anything else).  the light reflecting off objects in the center of your visual field is received at the fovea.  the rest of the retina contains mostly rods, with a few cones mixed in.  since the rods are more at the sides of your retina, and they are better at detecting light (even very dim points of light) and motion... when you are in the dark you tend to have really good peripheral vision.  look at the night sky on a clear evening.  concentrate on seeing the stars directly in front of you.  do any of them look not particularly bright?  now turn your head and try to see those dim stars through your peripheral vision.  they look much brighter, don't they?\n\nit takes a few moments for the eye to switch between primarily cone-vision and primarily rod-vision.  you can test this by going from a well-lit area to a dark area, such as enterring a movie theater from outside (daytime).  when you are outside, your eyes are adjusted for cone vision and you see lots of colors.  when you go into the theater, you can't see anything for a minute or so, then your eyes slowly adjust and the rods take over.  it gradually gets better... you can see shapes and recognize friends across the room, but everything is in shades of bluish gray.  if you then leave suddenly and enter a bright room or go outside, your eyes switch back to cone vision after a bit.\n\nthere is another thing i haven't mentioned: the pupils.  these are holes in the eye surrounded by smooth muscle.  the muscles control the size of the opening.  cameras work in a similar fashion... if too much light is coming in, things get "overexposed", it is hard to make out any detail.  you are effectively blind, until your eyes adjust.  it can be painful, too, if the amounts of light are significantly different.  you will probably notice this if you decide to fix your bulbs and continue to make nighttime trips to the bathroom.  when there is not much light, the pupil opening widens.  the maximum opening of the pupil is about ten times the size of the minimum opening.\n\nentering your dim bathroom from full sun is like going into the dark theater.  if you stay there long enough, your rods will kick in and you'll see just fine.  entering your dim (but lit) bathroom from complete darkness is like leaving the dark theater.  your cones take over.  in either case, you don't see "better" than usual, your eyes just adjust so that you are at your normal ability.
796290
A person suffering from night blindness cannot produce any 'visual purple' in his rods which are on his retina. Rods are used to see in dim light while cones are used to see colours vividly in bright light. Since his rods do not function properly, the person will not be able to see in dim light. e.g. when he is driving at night on a road with no street lights. However he will be able to see under bright light at night.
203476
I'm waiting on surgery to have my left eye operated on. i don't know any procedures around that will fix a catarrh without surgery as you need to have your bad lens removed and a new one put there. I've had my right eye done and can see through it perfectly. i cant see a thing through my left eye. the longer you leave it the worse it get, believe me i know.
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In the eye there r rods N cones. rods allow us to see details while cones colours! cats n dogs have more rods than human beings.
1174760
Improved sight in the dark? :)\nActually I'm not really kidding since men mostly have some 'color-blindness'. So you may have something there. After all the men needed a better night vision since they were the hunters/providers.(ref 1)\n\nActually what do you mean by color-blindness (check reference 2)?
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Bulls, like most animals are color blind.  \nHow do we know they are color blind?\nPeople and animals that can see in color have Rods and Cones in their eyes.  Cones see color, Rods see black and white.  Bulls don't have cones.\n\nNow if you'll turn to page 114 in your text book we will study the anatomy of frogs.  :-)
245897
i've heard about somebody who lost his sight because he saw a partial eclipse without using apropiate glasses...\nultraviolet and infrared rays coming from sun can damage your eyes...
208454
dunnerzplant pretty much has it right.  To give a more basic explanation, the retina has an array of "rods and cones" laid out like pixels on a tv screen, and they are all connected to the visual cortex that has a similar array of perceptive neurons that can piece all fo the signals together as a picture.\n\nDifferent cells in the retina have different chemicals that are sensitive to different colors, or wavelengths of light.  When light of that color strike that cell, the chemical does a slight shape-shift that ignites a mechanism to change the cell's output of neuroreceptors, liek a switch.  Once the light disappears, the photochemical shifts back to its latent state, and the perception of that color also ceases.\n\nIt's pretty cool stuff, really.  Any good Molecular and Cellular Biology textbook will give a good description of how the whole thing works.  I think even a basic college Biology text will give a rudimentary treatment of the subject.
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I'm not sure about correcting entirely, but this site says it helps those who have color blindness distinguish colors...\n\nhttp://www.colorblind.to/glasses.html
438458
General thought about looking directly at very bright light is correct. The lens of our eyes can project a many fold brighter image on the retina. This can damage the rods and cones in your retina and can even cause permanent damage to your vision.
347572
Actually, the reason for this is known.  There are two major types of light-sensing cells in your retina, called rods and cones.  Cones are specialized for color vision and detail-they are concentrated in the central portion of your vision, so that when you look directly at something which isnt moving, you can see it very clearly, in color and detail.  The rods are black and white, and are specialized for low-light detection of movement.  Since the cones are in the center of your vision, there are more rods in the periphery of your vision.  If you think about it, this makes perfect evolutionary sense, since you want to quickly detect things moving in your periphery, so you can react to an attack-because humans have such excellent detail vision, we can detect things in our center of vision even when they arent moving (many carnivores, such as dogs, hve a difficult time seeing stationary objects), so we dont need such good "movement" vision in the center.  This arrangement also explains why color disappeas in low light, because cones require bright light, while rods work in dim light.  In addition, this explains why, in a dark room, you can actually see better in your peripheral vision-because the concentration of cones in the center of your retina is pretty useless in low light.