My LCD monitor doesn’t have the ability to be bright enough to hurt my eyes - I don’t have any physiological reaction to looking at a pure white screen with maximum brightness.
But if I’m playing a video game or watching a movie that has a detailed view of the sun, especially if the camera is pointed right at it and other cues are given that you’re looking at the sun (like the way the simulated aperture changes in games with high dynamic range lighting), I have a physiological reaction to the image as if I were looking at the actual sun. My eyes will sting, I’ll feel compelled to wince, and sometimes my eyes will even water if I keep staring directly at it.
Now clearly the monitor has no more ability to sting my eyes when displaying a bright yellow ball than displaying a bright white screen. So what exactly is happening here? Is there some sort of automatic brain instinct that recognizes not the actual brightness of the sun, but visual cues that you’re looking at the sun, and engages that physiological reaction? Is this uncommon or do most people have this sort of reaction?
I know what you mean - the image of the sunon my TV screen seems brighter than a pure white screen. I’m not sure I’ve ever found it uncomfortabe, though.
If some people go out into bright sunlight it causes them to sneeze, and I believe this is am innate reaction to the sun that evolved from living in dusty caves/huts/etc that clears the nose to make it more effective for hunting and tracking.
At least, I saw something like that suggested in a documentary long ago. I’m not sure how accurate it is, but it would not surprise me at all.
Right, no, I understand that. The issue here is whether the image of the sun without the corresponding actual amount of sunlight can trigger the same reaction. But now that you mention it, I can also sometimes get a pre-sneeze feeling from looking at an image of the sun - a little tingling really - but not an actual sneeze. I generally don’t actually sneezes at the sun though.
The main issue I’m wondering I guess is that I thought the eyes/brain were conditioned to react to the extremely bright light your eyes would be receiving from staring at the sun, rather than your brain figuring out “oh hey crap that’s the sun, look away!” from the image/context without the correspondingly large amount of light.
You do have overload detection, but you also have a strongly conditioned response to the sun (learned over many years) to avoid those overload conditions. The brain just cannot tell the difference between the low-light screen and the bright retina-damaging sun at a quick glance, so it reacts conservatively. Which is why the game designers do it.
I think what you are experiencing is based on contrast and not on the total light your eyes are exposed to. If you are in a dark room and have been viewing a darkened scene on the screen then your eyes will become accustomed to the low light levels. Then when a comparatively bright “sunrise” appears on the screen it will result in a painful over stimulation of the retina. The discomfort may be accentuated because the brighter area is small making your eyes adjust slower because the total light exposure is not as high as if the whole screen were brightened.
This is the same thing that happens when you walk out of a movie theater into bright sunlight. At first you almost can’t see, but in a few minutes your eyes adjust (iris contracts) and you can see without problem. The same thing would probably happen if your screen went all white suddenly. Until your eyes adjust the light will seem painfully bright.