I don't know the answer to your question, sorry, maybe someone else will. But perhaps I can say a bit from the astronomical point of view, confirming that it is potentially dangerous, as astronomers often warn against this.
Lots of new age type sites suggesting it, and I think it's an ancient practice also. Here is a story of a present day Indian meditator who claimed to be able to look at the sun even in the daytime, not just at sunset and sunrise, without it harming him.
Swamiji and the Discovery of Sunyoga
And an example of the many new age type blog posts suggesting sun gazing as beneficial - but she suggests a milder practice than the one used by the Indian meditator at sunrise and sunset only, not gazing directly at the sun - and suggests that you can do it even when you can't see the sun because it is hidden behind something.
The Ancient Healing Art of Sun Gazing
But, just to affirm that staring directly at the sun is potentially dangerous, from astronomical point of view.
It has presumably the same risks as you have with solar eclipse - where astronomers advise us not to stare at the sun - except during the moment of totality when it is hidden behind the sun and all you can see is the corona. Also not to look at it with binoculars or a telescope - except of course when you use suitable filters at the sun side of the instrument designed for safe solar observations (and with those also you have to be careful to check that there are no flaws, no chinks in the filter).
Solar corona - this is the only time you can stare at the sun safely with the naked eye according to astronomers. File:Solar eclipse 1999 4 NR.jpg
Advice on how to make a solar filter for a telescope
Make a solar filter, The Sky at Night - BBC Four
So mainly - the issue is, brightness triggering reactions that can lead to reduced sensitivity to light, sometimes permanently. And then - the infra red - can literally cook the back of the eye for permanent damage. We don't have any pain sensors in the eye so you won't know if your retina is getting cooked by the sun.
Seems the bright light effects are the main issue rather than the heating, and in many cases, your vision may recover within a year or so.
Can a Solar Eclipse Really Blind You?
But can be permanent damage.
The obvious thing is to block the sun. If you block out the sun with a tree or house or some such, so you don't see it, then it can't damage your eyes. But whether that still counts as "sun gazing" I don't know.
It's not safe to watch the sun through clouds or reflected in water. Both of those can reflect and transmit the dangerous light. The thing is, UV light is invisible to us, so the sun could be dim in visible light and still bright in visible light.
And - at sunset and sunrise you get much less of the dangerous radiation. But - still not quite none at all.
Certainly people gaze at the sun at those times often for a fair while without harm, just enjoying a beautiful sunset - and watching the sun set or rise. I've watched the sun rise or set a few times :). But normally you don't just stare at it for many seconds or minutes on end even then, your eyes are moving around looking at different things.
You could watch it through the special glasses designed for solar eclipse viewing.
Or, as someone suggested in one forum thread (can't find it now) - why not gaze at Arcturus or Sirius? Far enough away to be of no danger to the eyes, but they are still stars / suns in their own right. Would this count as sun gazing?
Or stare at the Moon - it's reflected sunlight after all? Does this count as sun gazing?
None of those will damage your vision.
If you stare at the sun with peripheral vision - well at least it isn't going to damage the central most important part of your retina but you might lose peripheral vision. Keep moving your eyes around so the sun is never on one spot for long would also reduce the risk. But who wants to lose even peripheral vision?
I don't know the context. If someone does this - stares directly at the sun for any period of time - they are doing it with some risk to their own vision, that they might go blind - probably not totally blind, but might end up with a permanent blank spot in their vision, maybe right in the centre of your vision if you look directly at the sun. Even if perhaps some people manage to do it without going blind - online anecdotal evidence that some seem to be able to watch the sun for a while in this way without permanent eye damage. Still, you'd need some pretty good reason to take that risk knowingly.
Otherwise - if you want to be sure not to damage your eyes - try staring at the Moon, Arcturus, Betelgeuse, hide the sun itself behind something, or stare at the sun through safe filters designed for eclipse viewing - or using a telescope with a properly designed appropriate sun filter at the objective side (not at the eyepiece side, that is unsafe) - to make it safe for eclipse viewing.
All of those should be safe enough not to be a problem :). I'm not too sure about staring at it for long periods of time at sunset or sunrise, - sometimes it can be pretty bright even then, and the most damaging rays after all are invisible and you can't feel them - I wouldn't do that for minutes on end myself, especially every day as a regular habit, just in case.
Lots of new age type sites suggesting it, and I think it's an ancient practice also. Here is a story of a present day Indian meditator who claimed to be able to look at the sun even in the daytime, not just at sunset and sunrise, without it harming him.
Swamiji and the Discovery of Sunyoga
And an example of the many new age type blog posts suggesting sun gazing as beneficial - but she suggests a milder practice than the one used by the Indian meditator at sunrise and sunset only, not gazing directly at the sun - and suggests that you can do it even when you can't see the sun because it is hidden behind something.
The Ancient Healing Art of Sun Gazing
But, just to affirm that staring directly at the sun is potentially dangerous, from astronomical point of view.
It has presumably the same risks as you have with solar eclipse - where astronomers advise us not to stare at the sun - except during the moment of totality when it is hidden behind the sun and all you can see is the corona. Also not to look at it with binoculars or a telescope - except of course when you use suitable filters at the sun side of the instrument designed for safe solar observations (and with those also you have to be careful to check that there are no flaws, no chinks in the filter).
Advice on how to make a solar filter for a telescope
Make a solar filter, The Sky at Night - BBC Four
So mainly - the issue is, brightness triggering reactions that can lead to reduced sensitivity to light, sometimes permanently. And then - the infra red - can literally cook the back of the eye for permanent damage. We don't have any pain sensors in the eye so you won't know if your retina is getting cooked by the sun.
"Exposure of the retina to intense visible light causes damage to its light-sensitive rod and cone cells. The light triggers a series of complex chemical reactions within the cells which damages their ability to respond to a visual stimulus, and in extreme cases, can destroy them. The result is a loss of visual function which may be either temporary or permanent, depending on the severity of the damage. When a person looks repeatedly or for a long time at the Sun without proper protection for the eyes, this photochemical retinal damage may be accompanied by a thermal injury - the high level of visible and near-infrared radiation causes heating that literally cooks the exposed tissue. This thermal injury or photocoagulation destroys the rods and cones, creating a small blind area. The danger to vision is significant because photic retinal injuries occur without any feeling of pain (there are no pain receptors in the retina), and the visual effects do not occur for at least several hours after the damage is done
Eye Safety During Solar Eclipses
Seems the bright light effects are the main issue rather than the heating, and in many cases, your vision may recover within a year or so.
Can a Solar Eclipse Really Blind You?
But can be permanent damage.
The obvious thing is to block the sun. If you block out the sun with a tree or house or some such, so you don't see it, then it can't damage your eyes. But whether that still counts as "sun gazing" I don't know.
It's not safe to watch the sun through clouds or reflected in water. Both of those can reflect and transmit the dangerous light. The thing is, UV light is invisible to us, so the sun could be dim in visible light and still bright in visible light.
And - at sunset and sunrise you get much less of the dangerous radiation. But - still not quite none at all.
Certainly people gaze at the sun at those times often for a fair while without harm, just enjoying a beautiful sunset - and watching the sun set or rise. I've watched the sun rise or set a few times :). But normally you don't just stare at it for many seconds or minutes on end even then, your eyes are moving around looking at different things.
You could watch it through the special glasses designed for solar eclipse viewing.
Or, as someone suggested in one forum thread (can't find it now) - why not gaze at Arcturus or Sirius? Far enough away to be of no danger to the eyes, but they are still stars / suns in their own right. Would this count as sun gazing?
Or stare at the Moon - it's reflected sunlight after all? Does this count as sun gazing?
None of those will damage your vision.
If you stare at the sun with peripheral vision - well at least it isn't going to damage the central most important part of your retina but you might lose peripheral vision. Keep moving your eyes around so the sun is never on one spot for long would also reduce the risk. But who wants to lose even peripheral vision?
I don't know the context. If someone does this - stares directly at the sun for any period of time - they are doing it with some risk to their own vision, that they might go blind - probably not totally blind, but might end up with a permanent blank spot in their vision, maybe right in the centre of your vision if you look directly at the sun. Even if perhaps some people manage to do it without going blind - online anecdotal evidence that some seem to be able to watch the sun for a while in this way without permanent eye damage. Still, you'd need some pretty good reason to take that risk knowingly.
Otherwise - if you want to be sure not to damage your eyes - try staring at the Moon, Arcturus, Betelgeuse, hide the sun itself behind something, or stare at the sun through safe filters designed for eclipse viewing - or using a telescope with a properly designed appropriate sun filter at the objective side (not at the eyepiece side, that is unsafe) - to make it safe for eclipse viewing.
All of those should be safe enough not to be a problem :). I'm not too sure about staring at it for long periods of time at sunset or sunrise, - sometimes it can be pretty bright even then, and the most damaging rays after all are invisible and you can't feel them - I wouldn't do that for minutes on end myself, especially every day as a regular habit, just in case.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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