why are eye balls different in colours?
960988
http://answers.yahoo.com/my/my;_ylt=AtAD8KWygLwBW.vQ.lHtrVUezKIX
65939
The eye has different types of receptors for color and brightness. The color receptors are sensitive to difference in the wavelength of light, much as the brightness receptors are sensitive to the difference in the brightness. \n\nDo you see green as everyone does? Not quite. There are some people who are color blind.\n\nFrom the wikipedia:\n\nPrimary colors are not a physical but rather a biological concept, based on the physiological response of the human eye to light. The human eye contains receptors called cones which normally respond to red, green, and blue light. Humans and other species with three such types of color receptors are known as trichromats. Although the peak responsivities of the cones do not occur exactly at the red, green and blue frequencies, those three colors are chosen as primary because they provide a wide gamut, making it possible to almost independently stimulate the three color receptors. To generate optimal color ranges for species other than humans, other additive primary colors would have to be used. For species known as tetrachromats with four different color receptors, one would use four primary colors. Many birds and marsupials are tetrachromats and it has been suggested that some female humans are born as tetrachromats as well, having an extra receptor for yellow. On the other hand, most mammals have only two types of color receptors and are therefore dichromats; to them, there are only two primary colors.
227705
Yes, the colour of the eyes can change by using contact lenses. I don't know if it can change by a physical way.
904667
No. But that does NOT mean bulls are colorblind. Many mammals cannot tell the difference between red and green, but do see more than black and white.\n\nMammals in general have poorer color vision than birds and reptiles. This is believed to be because they were nocturnal scavengers early on in evolution and eventually lost 2 of the 4 types of cells in the eye that allow us to see color. These are known as cone cells.\n\nSome primates, such as humans, have regained a 3rd type of cone cell. Thus allowing them to tell the difference between red and green. Being that this is an evolutionary new cone, it is no surprise that this newer color distinction is more commonly lost than the older blue and yellow.
1184007
The colored part of your eye is the iris, and all it does is control the amount of light that passes into the eye by varying the size of your pupil.  Light passes through that opening to the retina at the back of the eye where the rods and cones convert the lightwaves into the nerve signals that your brain recognizes as objects, colors, etc.
382134
I'm not really sure, but from what I understand it to could be some chemical changes in the body based on your feeling and what horomones your brain is releasing. My teacher told me that some teenagers have eyes that change color because of hormonal changes, and when they become adults, their eyes will probably remain one certain color. \n\nIf you are interested in eye genetics here is a link:\nwww.anthro.com/evo/inherit.html\n\nMy eyes are completely brown and my favorite eyes are blue.
949480
Many babies are born with blue eyes that later change color. this is what happened to me, they were blue now they are hazel. Eyes change color just as hair does, and yes you might have hazel eyes
343860
Sorry for the somewhat inappropriate answers you got. Well, what can we do? this world is ful of diverse mindsets you know.\n\nFirst of all, congratulations for getting your question featured on the Yahoo! Homepage. Keep on asking good questions!\n\nNow, to answer your question, some peoples' eye colors change without any apparent reason. As you might be knowing that traits like color of skin, eye (iris) color depend on your genes i.e. these are genetic traits, certain changes in genes might directly affect these outer morphological (=phenotypic) traits. The changes are so slight that they often go unnoticed. Apparently yours got noticed.\n\nBut, if your eyes are suddenly "loosing colors" i.e. are undergoing depigmentation, that "might" be a case of concern. Here is a link where you might get your question answered- http://www.straightdope.com/classics/a971205.html
896732
I have a green eye. Sometimes it goes blueish, but it's hardly ever brown. I have another one that's just like it!\n((Guess Malibu wins this one!))
10879
Most likely they simply measure the number of rods and cones. Since cones are resonsible for color vision and differernt kinds of cones are sensitive to different wave lenghts it should be trivial (in an adademic sense) to determine what range of color a particular eye ball can detect.
160897
On a more scientific basis they just discovered that humans have a wide varity in the ratio of color receptors in the eye.  Some have mostly red color receptors, some have lots of green and blue.  I'm guessing that this could affect how we individually precieve color and influence our preferences.  Anyways, you might find the "dewey color system" interesting and it might offer you more insight.  http://www.deweycolorsystem.com/
334686
My.. Don't you have a textbook for that?\nAnyway, I went to check my O level text book and this is what I got.\nI've written out a not so short description.\nBut you can skip the junk if you only want to know where the rods in our eyes are found.\n\nand the answer is.. \nrods in our eyes are found in the retina, which is the innermost layer of the eyeball.\n\nThere! hope I've helped!\n\n(THE RETINA)\nThe innermost layer of the eyeball is the retina, which is light sensitive. The retina is the layer on which images are formed. It consists of photoreceptors or light-sensitive cells. These are connected to the nerve-endings from the optic nerve. This nerve conveys impulses to the brain when the photoreceptors are stimulated.\nThere are two kinds of photoreceptors: the RODS and the cones.\n\nRODS contain visual purple, the pigment concerned with vision in dim light. Light causes bleaching of visual purple which is involved in light detection. In bright light, all the visual purple is bleached. Thus, when a person enters a dark place from a bright one, he may not be able to distinguish the objects around him for some time. This is because it takes a while for the visual purple to be formed again in the rods.
1073050
the most important diffrences between light colored eyes and dark eyes are the pigmentations of the iris and also the diameter of stroma layer of cronea. having thiner stroma layer and less pigmentations in blue eyes may result in higher injury of retina from light(especially UV).
570792
There are also, rarely, some people whose eyes appear aqua or violet, as well as the pink-eyed albinos. Eye color is determined by the concentration and distribution of melanin in the iris, which affects how light is reflected by the iris. The limitations on eye color are probably the same as the limitations on skin color, which is all controlled by melanin.\n\nHere's a link to an interesting article on eye color.
608083
Eye color is the pigmentation and reflections of particles in your eye. Basically the lighter the eye the less pigmentation is in that eye.  BLue eyes have less pigmentation than brown eyes. The way that the color is reflected gives the different apperance of the eye color. \nMy eyes are green. They arecool.
723382
First of all, eye color can change with age. Second, it's more complicated that the simple brown / blue description that they give in high school biology class. So I suspect that the answer is yes.
172977
what color are your eyes?