When its dark and suddenly your eyes are exposed to light, why does it hurt? I know your pupil goes slamming shut, but why does it hurt? Is it the pupil? Is it something in my eye? I understand a person squinting to limit the amount of light coming in, but I don't understand the pain.
Sensory overload. Your pupil is too wide because it's used to darkness. So too much light enters the eye, which causes overstimulation of the photo receptors in the retina. This causes excessive electric impulses to the optic nerve, and that hurts. Squinting is probably an evolutionary response to prevent damage.
I don't get it. If its excessive, why doesn't it keep hurting? The brightness of the light doesn't change.
I'm guessing here using the info from Enmos' post so I might be completely wrong but.. It's only excessive to your wide pupils, which were wide only because they were in darkness. Once your pupils adjust and narrow, and cause less light to stimulate the photo receptors, it's no longer excessive and no longer hurts.
In humans and many animals (but few fish), the size of the pupil is controlled by involuntary constriction and dilation of the iris in order to regulate the intensity of light entering the eye. This is known as the pupillary reflex. In normal room light, a healthy human pupil has a diameter of about 3-4 millimeters, in bright light, the pupil has a diameter of about 1.5 millimeters, and in dim light the diameter is enlarged to about 8 millimeters. The narrowing of the pupil results in a greater focal range. WIKI
When a photon hits off of the retina, a number of changes occur. If there is a sensory overload, there are molecules that are set of into a chain-reaction producing an oveload of proteins.
Anytime you do something to yourself that you shouldn't do, pain happens. So when you look into a very intense spotlight it will cause you pain .
You should also note that your eyes are 'absorbing radiation', your pupils resizing lessens the amount of radiation that is absorbed. This is why if you stare at a computer screen for a long time you can end up light sensitive.
Because it is damaging.. the pain is there to tell you to stop looking into the sun or to get away from the loud noise, etc.
You've never had a headache ? lol The brain has no pain receptors probably because when the brain is damaged something has happened you probably can't get away from anymore.. Evolutionarily seen, it is nonsense to put pain receptors in the brain.
it has proven itself to be beneficial in a evolutionary sense, thats why... (less apes going blind) the human body is just a bid biochemical machine that you (the brain) controls, pain is just a interpretation of signals coming from your body. its a self protection mechanism that makes sure you don't kill yourself by accident. When looking in strong light with dilated puils the sensory cells are overexposed to a lot of light possibly resulting in damage, to avoid this from happening the brain gives you the feeling of discomfort making you to change whatever your doing wrong
btw: some people sneeze when they look into strong light, thats a reaction cave men developed, when they came out of the cave into to the relaivly stong light they would sneeze to get rid of dust/dirt in the airways...
you feel pain when you look at the sun because it's not good to look at it just like it's not good to touch fire. i'm not a brain, i control my brain. according to evolution the meaning of life is to survive, but what is the meaning of survival? i think god is much better than evolution.
