What causes people to get red-eyes in photographs and why is it especially common with blue and green eyes?
926398
That is a result of the flash being so quick that the eyes remain wide open and the inside of the eyes (retina) with its rich blood vessels is illuminated by the light. That makes the devilish looking red spots. People with light colored eyes are more likely to get a lot of light inside the pupil of their eyes and show up with red eyes.\n\nShooting the photo in available light not flash, using a camera that has a preflash to get the pupils to contract, or not shooting the picture head-on will avoid it. If you get it then photo imaging software can easily remove it.
6085
"There are hundreds of reasons why someone might have two different-colored eyes, known as hetero-chromia, says Dr. Richard Hertle, a pediatric opthamologist at the National Eye Institute in Bethesda, Maryland. Two of these are direct injury to the eye or an underlying disease that affects the eyes."\n\nSee link for further information.
1013395
If you're talking about redeye in photographs, this is caused by light from a flash reflecting directly off the retina in the eye, and into the camera.  The red is caused by the blood vessels in the retina.
9382
Red eye occurs when the level of the flash is at the exact same level/angle of the subjects eyes(retinas). It's the light from the camera bouncing off the back of the eyes and reflecting back into the camera's lense. Anyone in a picture can come out with red eye.
546665
The genes for eye color determine the amount of melanin, a dark brown pigment, produced in the iris of the eyes. Blue eyes are due to a lack of melanin, while brown eyes indicate melanin-rich irises. Thus, people with darker hair and skin have higher levels of melanin and tend to have brown eyes, while people with lighter hair and skin have lower levels of melanin and usually have lighter colored eyes.
1041372
Green eyes are more rare.  There is not an actual gene for green eyes, protein differences cause some eyes to be green.
49350
Any eye colour other than brown is caused by an absence of pigments in the iris. People inhabiting extreme latitudes usually have lower general pigmentation in order to get sufficient Vitamin D uptake through ultraviolet light. This is accompanied by a tendency to have lighter hair colour and less pigments in the iris.\n\nYou might call it a genetic defect which has proven useful.
208190
I'm colour blind actually....I have a very hard time with shades and red-greens.  I see colour differently than you do.  Or don't see as the case may be.
1164622
Judging by the fundamental importance of the color *green* to life on this planet, I would say green-eyed people got you blue-eyes beat.\n\n(P.S. I have brown eyes, so I'm taking this whole thread as just a harmless joke.)
1047284
There are two issues here, human physiology and semantics.  Stastically speaking, most people's eye will respond to a light stimuli in the same way as anothers, with a certain percentage of people having certain genetic deformities that cause color blindness.  The issue of semantics is that even in the presence of wide variations in response to light stimuli we agree upon certain naming conventions when referring to a common object, for example, we both look at an apple and refer to it's color as red, regardless of the exact response it causes in our visual system.
488645
You only get red eye if the person looks directly at the lens, and the flash reflects into it.  \n\nA dead person is not looking directly into anything. \n\nQuit taking pictures of them, it's not normal.
256405
my own understanding to this is - and i might be wrong - it has an affect. i based this on Albinos, they lack pegimintation (melinen) in their skin and eyes (which gives them pink or red eye colour) and they have major eye-sight problems and sun can affect them alot. so i would assume the less pigement u have (i.e. blue) the greater affect u will have by sun (even if it is very little) but surely there is a difference.
37596
You could use VISINE eye drops for redness...caused by reading too much, etc.
1170811
If you are meaning the color of a person's eye, it is the iris that has the color that others see. If you mean someone having two different colors of eye, that is called heterochromia.
197523
Everyone sees everything a little differently than others.  As for colours, it's how your eyes may process light and how your brain may interpret that light.  \n\nIf you're seeing blue while I see red or vise-versa, there's a big problem because those two colors are opposites (actually red and cyan, which is kinda blue).
1129008
Genetics.  Green eyes are a genetically recessive trait, just like blue eyes are.  Someone in your family also has green eyes.  Possibly a grandparent or great-grandparent.
144874
A major cause of light sensitivity in people is just that they don't have a lot of pigment in their eyes.  If you have fair skin/hair and light irises, this could easily be the cause.  If this is something that you just started experiencing, you should know that there are many diseases/infections that have photosensitivity as a symptom.  If that's the case for you, make an appointment with your eye doctor.