I was wondering, has anyone every really gone blind from staring at the sun? How long would they actually have to look at it on order to get blind, and would they be blind forever? I know if I star at it for a while and look away I’ll see spots for a while,but they eventually go away
I said it before and I’ll say it again.
You can get permanent visual field cuts from retinal damage with less than 15 seconds of exposure. These individuals are generally out in strong sunlight, and they will forever see the afterimage of the sun in the center of their vision. Makes it a bitch for driving, and reading too. It doesn’t hurt, it just plays hell on the retina. Pain from bright light is due to the rapid constriction of the iris as it tries to cut down on the light entering, but if you’re already out in sunshine, looking at the sun won’t be painful, 'cuz your iris will be about as constricted as it can get.
Examining the retina in these patients is kinda neat, it looks like somebody had a grassfire right in the middle of a red-orange lawn, leaving a black burned space right over the macula, where the center of vision is.
I have done some research on this topic. From what I have found, no one has ever gone totally and permanently blind from looking at the Sun. Solar retinopathy (retinal damage from looking at the Sun) is, however, a complicated issue.
The damage comes mostly from ultraviolet light which can damage chemicals in your eye. Many people claim erroneously that infra-red can cook your eye, but this is almost certainly not true; IR light is not absorbed well by your eye. In general, your pupil constricts so rapidly that there isn’t time to hurt your eye easily. Staring at the Sun can indeed damage your retina, but there are many cases of full recovery from people who have looked at the Sun for long periods of time. Interestingly, the pupil blocks just barely enough light (on average) to prevent damage; so in some of the population the pupil does not constrict enough. The lens also yellows with age, protecting older people more from the UV light. Therefore, children are more susceptible to damage than adults.
All in all, better safe than sorry; avoid staring at the Sun.
The reason solar eclipses are dangerous is because during totality the pupil dilates, letting in more light since the Sun is blocked. When the Moon slips off the Sun, even the thin sliver of solar surface can be enough to flood your retina with damaging photons, since the pupil is wide open.
A very interesting website with a lot of information has been put together by astronomer Andrew Young. He also puts to rest the legend that Galileo went blind by looking at the Sun; he has excellent counter-evidence for that.