what happens to the accommodation of the human eye when exposed to red light?

Question

-explain how the eye responds whether it relaxes or gets stimulated to red light ,if true ,how?

-pls explin only with respect to human eye
-and to add on can u correlate this concept to duochrometest?

Answer 1

The duochrome test uses red and green light. The green light focuses slightly in front of the retina and the red light focuses slightly behind the retina. Therefore if a person was too nearsighted, the red side of the chart would appear clearer than the green side. The red light should not affect accommodation much since it is focused behind the retina, accommadating would not help bring it into focus on the retina. Green, however, could be focused on the retina with accommodation being used to move the image back to the retina.
The goal of the duochrome test is to have the patient report both sides of the chart equally clear or distinct. This means the red and green are straddling the retina equally on each side and the patient is acting as an "emmetrope".
~almost O.D.

Answer 2

Sorry, but K.J.Jeyabaskaran's response was so full of misinformation, I first have to correct it. First, red wavelengths are low energy (long wavelength, low frequency), not high. Second, the different energy of the wavelengths has nothing to do with the response of the pupil. And none of this has anything to do with why danger signals are red in color.

The problem with light of any isolated color (not just red), is that if it occupies a narrow bandwidth of color, the light can be very bright in those wavelengths, but since the other wavelengths are absent, the overall light does not appear as bright, and it will not trigger the eye's normal accomodation and defense mechanisms for overbright light (contraction of the pupil, blinking, squinting, or even turning away as you would do if you recognized how bright the light was). For *very* bright light of a *very* narrow wavelength, (like even a low-powered laser) this can cause damage to the retina.

As for the duochrome test ... I am not an optometrist, but my understanding is that this is for measuring the chromatic aberation of the focusing aparatus of the eye (the cornea and lens). Chromatic aberation is the fact that red wavelengths and green wavelengths (long- and medium-length) focus differently, and this needs to be taken into account when making prescription lenses, or else black letters will appear darker against a red or a green background.

Answer 3

Well, I am not an eye doctor, but I do remember one thing from being in the military about red light. For some reason, most persons' eyes, or more precisely their pupils. will not contract in response to red light. Whenever we were getting ready for night maneuvers, we would get ready in a red light environment. This way we could read maps, check equipment, etc and not lose our "night vision". This way we could immediately go when our preparations were done and not wait a long time for our eyes to adjust after leaving whatever rally point we were at.
So, for some reason [let a doctor come on and explain why], the eye does not react in a similar fashion to red light that it would to white light or another color.

Answer 4

As per the quantum theory of light, the energy due to red colour light is very high. As per the wave theory, the wavelength is short and frequency is more. So, whenever human eyes are exposed to red light, the aperture of the eye ball (the hole in the eye ball throught which light passes) is contracted to tolerate the high energy of red colour. Even then it irritates the eye. The red coloured light is having the potential to travel longer distances without any dispersion in the air. That is why the danger light signals are in red colour.

Answer 5

A Professional Photographer may be
able to help out with an explanation of
why a "Red Safe Light" in a developing
"Dark room" doesn't spoil the photos.

Answer 6

Red has the lowest freq. of the visible spectrum, so the pupil of the eye expands since there isn't much energy in the light. Red lights are used for stargazing since they let you see more.

You could ask an astronaut.
:)