OK, now that the eclipse is pretty much over, can someone tell me...

[LAS14]

... how long you need to look at the sun to get eye damage? I can see not wanting to publish this kind of news prior to the eclipse, because you can't count on people behaving. But we've all "peeked" at the sun. And most of us of a certain age have watched solar eclipses through smoked up glass, right? You actually can't easily look at the sun for more than a fraction of a second, because it is too uncomfortable. Right?

tia
las

[cwydro]

1. I wouldn't dare look at it. Period.

It took willpower to gather the courage to use the eclipse glasses lol.

[bearsfootball516]

2. I believe that

Staring for even just a couple minutes is enough to cause permanent damage, if you can stand to actually stare for that long. Maybe not full blindness, but damage.

[pnwmom]

5. Permanent damage can occur within seconds -- and not be apparent for hours or days.

[jpak]

3. 0.000000000000000000 seconds

yup

[radical noodle]

4. They're saying a few seconds can harm your eyes permanently.

Might not totally blind you in that length of time but there could be some damage.

[Binkie The Clown]

6. Your eye has a lens focused on your retina. Hold up a lens and focus it on a piece of paper.

How long before the paper bursts into flames?

[JustABozoOnThisBus]

14. I did that, except I focused it on a brick.

I used my reading glasses (drugstore cheaters) as the lens. The image on the brick showed the moon partially covering the sun. Maybe we had an 80% eclipse in Detroit.

[LAS14]

7. OK, so why aren't thousands of us oldsters who used smoked glass suffering retina damage?

[LanternWaste]

9. Often, smaller degrees of unrecognizable damage are ignored as "no damage at all."

Often, smaller degrees of unrecognizable damage are ignored as "no damage at all," much as sufferers of multiple concussions over a period of time are completely unaware of the damage done-- simply because they as layman do not recognize it as such.

[defacto7]

10. Oh but they are!

There's a hell of a lot of retinal damage. Some of it accumulates over time, sometimes it's the retina finally tearing away from the eye because of previous damage that waits till your eyes are more vulnerable.

[hlthe2b]

8. Very different from looking at direct sun, which triggers reflex blinking, tearing, constriction

& causes you to look away.

The eclipsed sun still provides intense radiation to the eye, but because of the partial moon coverage, your eye reflexes are not triggered and the damage is done--very quickly.


http://scienceline.ucsb.edu/getkey.php?key=3269

Obviously, no one has done a study to measure the exact time before damage or blindness occurs, but doctors collect information after events like the 1999 solar eclipse, when people who stared directly at the sun for several minutes went to see their doctor. In one study, about half had permanent damage. Short-term damage can be easily prevented: never look directly at the sun. During sunsets, when the intensity of ultraviolet light is lower due to scattering, avoid looking directly at the sun for more than a few minutes at a time. Sunglasses and camera filters do not prevent short-term damage, and may make it more likely by dilating your pupil and/or allowing you to stare at the sun longer without pain.

[LAS14]

11. OK, damage "after several minutes," doesn't warrant the advice, "never...

... look directly at the sun," if you look for only a second or two. I can see not giving the advice "don't look for more than a few seconds," because you can't trust people to make judgments. Better to make it black and white for general consumption. But I just want accurate info.

[hlthe2b]

12. As with all health phenomen, there are some who take very little time/damage

and others who might take a little more. Lots of other issues come into play--intensity of sun, cloud cover, altitude and potentially other factors. Note the article was largely for normal sun and an eclipsed sun is far more dangerous--for the reasons already outlined.

Want to roll the dice?

In the words of the late, great, PT Barnum (whether he actually said it or not), "a sucker is born every day"...

[defacto7]

13. Too many variables to say exactly how long.

Some people can't even go out in the sunlight without sun glasses or they could loose their sight. It depends on the pigment in your eyes, altitude, air quality, even the state of the sun cycle. There's no safe limit.

[zipplewrath]

15. 2 seconds

That's an approximation. Various factors will influence this including what you were looking at before, how much of an eclipse you view, etc. Somewhere around 5 seconds you'll be in trouble. Try this, on a normal day, how long can you truly look at the sun without closing your eyes or looking away. 'tain't long I'd bet.

[LAS14]

16. Thanks! Exactly the sort of answer I was looking for....

... and without this information, the photo of Trump looking at the sun (probably a 10th of a second) and surviving will be proof that science can't be trusted.