Instant 'After-images' on the Retina?

[Connor]

yeah, but most people can't actually see well in the dark, pick out objects and whatnot (like me, always tripping over crap). Some people however, can see pretty good in the dark because of infrared radiation. This was discovered in some military folk who didn't need night vision goggles.

 

that's awesome about your teacher's teacher by the way

[CanadaAotS]

There are alot of wierd eye things out there. An example is myself, when I see a computer monitor on refresh rate higher then 60 Hz I can see the screen flicker... You'd think it would be smoother higher it is, may be cause I'm used to TV.

 

Anyways I wish I could see some infared, I've heard of artificial eyes being made that could be configured to take in infared or whatever other bandwith you'd like. They've only managed 256x256 resolution in black and white so far... very interesting though

[jonnyl]

Well these trails/ghosting drives me the f*** nut still, after 8 years.

 

No one who experience these symptoms have gotten an answer to what is causing them. Aaargh.

[Sigma6]

Are these like the things were you wave your hand in front of you and then see like an outer-side of the outline of the arm following slowly behind, 'cause i get that sometimes and people look at me wierd when i do it, i enjoy it but i also want to know what it is

[Sigma6]

http://www.nioeyes.com/eyes/care/qanda.htm#trails%20or%20tracers

[Edtharan]

Our eyes use chemicals in the rods and cones in the retina to detect light. These work by breaking up when light of a particular wavelength hit is (red, gree, and blue). The chamicals are actually very similar to one an other and some people have some that respond roughly equally to 2 different wavelengtha, these people are called colour blind.

 

Now as these chemicals have to break up when the light hits them (and stimulating the nerve cells), this means that the chemical gets used up, but the eye makes more of it.

 

So if you look at an object that has a lot of contrast (say a white shape on a dark page or dark computer screen), then the light sensitive chemicals that are used to detect the ligt get used up wher the white object is. When you shift your gaze to something else (say a white coloured wall) the light from the wall activtes the chemicals all over the eye, but where you had the white object before you have used up a lot of the chemicals there and so the activity there is lower than elsewhere in your feild of vision. You see this as a darker patch.

 

Now we have 3 colour receptors in the eye and if one of those colours gets used up by the others don't, then if we look at a white area we will see the unused receptors giving a strong output and the receptor of the colour that we were looking at will give us a weak output. So if we were looking at a blue object, then we will see a Red/Green (which is yellow) after image. If you were looking at a yellow object then the after image would be blue.

 

If, for some reason your eyes are not replenishing these chemicals fast enough, then you will get these after images more often.

 

But still, go see a doctor if you are at all concerned about this.

[mrblond5311]

Our eyes use chemicals in the rods and cones in the retina to detect light. These work by breaking up when light of a particular wavelength hit is (red' date=' gree, and blue). The chamicals are actually very similar to one an other and some people have some that respond roughly equally to 2 different wavelengtha, these people are called colour blind.

 

Now as these chemicals have to break up when the light hits them (and stimulating the nerve cells), this means that the chemical gets used up, but the eye makes more of it.

 

So if you look at an object that has a lot of contrast (say a white shape on a dark page or dark computer screen), then the light sensitive chemicals that are used to detect the ligt get used up wher the white object is. When you shift your gaze to something else (say a white coloured wall) the light from the wall activtes the chemicals all over the eye, but where you had the white object before you have used up a lot of the chemicals there and so the activity there is lower than elsewhere in your feild of vision. You see this as a darker patch.

 

Now we have 3 colour receptors in the eye and if one of those colours gets used up by the others don't, then if we look at a white area we will see the unused receptors giving a strong output and the receptor of the colour that we were looking at will give us a weak output. So if we were looking at a blue object, then we will see a Red/Green (which is yellow) after image. If you were looking at a yellow object then the after image would be blue.

 

If, for some reason your eyes are not replenishing these chemicals fast enough, then you will get these after images more often.

 

But still, go see a doctor if you are at all concerned about this.[/quote']

 

 

Since these cases normally deal with dim lit rooms or darker objects couldn't vision purple (the chemical produced by your brain that helps you see in the dark) have something to do with the color contrast and the after effect since he's going from dark to light or vice versa? The chemical change could explain why it's hard for other chemicals to be replenished and explain the after effect if there is vision purple being switched on then off since it requires light to destroy it. Could his eyes be "over reactive" to darkness; especially since he quoted he's very sensitive to light. Synthesis, do you experience any pain or discomfort while this is going on?

 

I was never really sure what triggered vision purple - the presence of darkness or the contrast between light and darkness. Could focusing on a dark object enable your brain to produce vision purple even in daylight? Any help?

[Edtharan]

Here is a web sight (pun intended) about how your eyes work.

http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html

 

The rods in your eyes are what allow you to see in the dim light. They are much more sensitive than the cones are, but only detect brightness, not colour.