# You'll burn your eyes out! **URL:** \ **Category:** Factual Questions\ **Created:** [August 7, 2006, 5:29pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720 "2006-08-07T17:29:48Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![myrnajean](https://avatars.discourse-cdn.com/v4/letter/m/c57346/32.png) [@myrnajean](https://boards.straightdope.com/u/myrnajean)\ **Post date:** [August 7, 2006, 5:29pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/1 "2006-08-07T17:29:48Z")
I’ve always heard that you should shut the cover on a copier machine before pressing the start button, or some unknown damage would happen to your eyes, and of course NEVER look at the sun, your retina’s will crisp up and fall out of your head. You can’t even look at the moon with a telescope, unless you buy the special moon filter. Is any of true? And if so, why? What really happens if you look directly at a solar eclipse, other than seeing those spots in front of your eyes for a while, …(okay yes, I’ve done it) Am I doomed ? ---
**Author:** ![Clockwork\_And\_Candy](https://avatars.discourse-cdn.com/v4/letter/c/b782af/32.png) [@Clockwork\_And\_Candy](https://boards.straightdope.com/u/Clockwork_And_Candy)\ **Post date:** [August 7, 2006, 5:38pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/2 "2006-08-07T17:38:15Z")
Not sure about the others, but as a person who has, on multiple occasions, xeroxed his face with _open_ eyes, I can say that copier machine one isn’t true. Or, at least my eyes seem to be fine. ---
**Author:** ![FormerMarineGuy](https://avatars.discourse-cdn.com/v4/letter/f/65b543/32.png) [@FormerMarineGuy](https://boards.straightdope.com/u/FormerMarineGuy)\ **Post date:** [August 7, 2006, 5:44pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/3 "2006-08-07T17:44:01Z")
From [NASA](http://sunearth.gsfc.nasa.gov/eclipse/SEhelp/safety2.html) > [@](#): > > However, observing the Sun can be dangerous if you do not take the proper precautions. The solar radiation that reaches the surface of Earth ranges from ultraviolet (UV) radiation at wavelengths longer than 290 nm to radio waves in the meter range. The tissues in the eye transmit a substantial part of the radiation between 380 and 1400 nm to the light-sensitive retina at the back of the eye. While environmental exposure to UV radiation is known to contribute to the accelerated aging of the outer layers of the eye and the development of cataracts, the concern over improper viewing of the Sun during an eclipse is for the development of “eclipse blindness” or retinal burns. > [@](#): > > The only time that the Sun can be viewed safely with the naked eye is during a total eclipse, when the Moon completely covers the disk of the Sun. It is never safe to look at a partial or annular eclipse, or the partial phases of a total solar eclipse, without the proper equipment and techniques. Even when 99% of the Sun’s surface (the photosphere) is obscured during the partial phases of a solar eclipse, the remaining crescent Sun is still intense enough to cause a retinal burn, even though illumination levels are comparable to twilight [Chou, 1981, 1996; Marsh, 1982]. Failure to use proper observing methods may result in permanent eye damage or severe visual loss. This can have important adverse effects on career choices and earning potential, since it has been shown that most individuals who sustain eclipse-related eye injuries are children and young adults [Penner and McNair, 1966; Chou and Krailo, 1981]. ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [August 7, 2006, 6:01pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/4 "2006-08-07T18:01:06Z")
> [@myrnajean](#): > > You can’t even look at the moon with a telescope, unless you buy the special moon filter. I’ve looked at the full moon through a 5 inch reflecting telescope without a moon filter. I spent maybe 3 or 4 minutes looking at the moon and was dazed for a few hours afterwards. The moon is very bright, I don’t think I could have looked for much longer than I did. I bought a moon filter after that. ---
**Author:** ![Shoeless](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/shoeless/32/7099_2.png) [@Shoeless](https://boards.straightdope.com/u/Shoeless)\ **Post date:** [August 7, 2006, 7:28pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/5 "2006-08-07T19:28:41Z")
[The master speaks.](http://www.straightdope.com/classics/a1_235a.html) ---
**Author:** ![Aton11](https://avatars.discourse-cdn.com/v4/letter/a/c2a13f/32.png) [@Aton11](https://boards.straightdope.com/u/Aton11)\ **Post date:** [August 7, 2006, 10:53pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/6 "2006-08-07T22:53:55Z")
**I read that it is SAFE to stare at the Sun for up to several minutes during the timeframe of about 15 minutes after sunrise, and 15 minutes before sunset. It’s been stated that UV radiation at those times is relatively weak and will not harm the retinars. Is that true?** ---
**Author:** ![susan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/susan/32/17537_2.png) [@susan](https://boards.straightdope.com/u/susan)\ **Post date:** [August 7, 2006, 11:09pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/7 "2006-08-07T23:09:37Z")
My college haiku on the subject, by which you may infer that I did copy my face, with my eyes open: three bright bleaches each blink the eye sightless circle visual purple ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [August 7, 2006, 11:39pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/8 "2006-08-07T23:39:57Z")
> [@myrnajean](#): > > You can’t even look at the moon with a telescope, unless you buy the special moon filter. You can, and there’s no permanent damage, but trust me, you don’t want to. Especially if you’re in a dark observatory- you’ll be stumbling around in the dark around fragile and expensive equipment. Eating that mayonnaise-based potato salad that’s been sitting out in the sun for hours isn’t likely to do permanent damage, either- doesn’t mean it’s something you’d want to do 😉 > [@](#): > > What really happens if you look directly at a solar eclipse, other than seeing those spots in front of your eyes for a while, …(okay yes, I’ve done it) Am I doomed ? If the spots eventually went away, and your vision is still normal, you’re probably not doomed. The main reason people are more likely to damage their eyes when looking at a partially eclipsed Sun than looking at the Sun any other time is that, normally, there’s not that much to see if you look directly at the Sun, so you look away quickly. During an eclipse, there’s something interesting to see, so people watch longer. A glimpse of the partially eclipsed Sun isn’t going to permanently damage your eyes, any more than a glimpse of the Sun at any other time would, as long as you don’t stare at it. And the _totally_ eclipsed Sun _is_ safe to look at without special protection. It’s only the partial phases of the eclipse that are dangerous. > [@Aton11](#): > > **I read that it is SAFE to stare at the Sun for up to several minutes during the timeframe of about 15 minutes after sunrise, and 15 minutes before sunset. It’s been stated that UV radiation at those times is relatively weak and will not harm the retinars. Is that true?** It’s not UV radiation that causes retinal burns- it’s infrared. The red color of the Sun at sunset is caused by blue light being scattered through the atmosphere- short wavelengths are scattered more than long ones. It’s true that you would get less UV at sunrise or sunset, but not less infrared, and infrared is what causes retinal burns. I personally would not deliberately stare at the Sun at any time without proper eye protection. It’s just way too risky, and what do you get out of it, anyway? But I don’t worry that a brief accidental glimpse of the Sun will make me go blind, either. During an eclipse, it’s so easy to make a safe viewer- all you need is two index cards, with a pinhole punched in one of them. Hold the one with the hole in it so the sunlight falls on it (Note: DO NOT look through the pinhole), and catch the projected image of the Sun on the other card. ---
**Author:** ![flex727](https://avatars.discourse-cdn.com/v4/letter/f/258eb7/32.png) [@flex727](https://boards.straightdope.com/u/flex727)\ **Post date:** [August 8, 2006, 1:20am UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/9 "2006-08-08T01:20:23Z")
> [@Anne Neville](#): > > The main reason people are more likely to damage their eyes when looking at a partially eclipsed Sun than looking at the Sun any other time is that, normally, there’s not that much to see if you look directly at the Sun, so you look away quickly. During an eclipse, there’s something interesting to see, so people watch longer. A glimpse of the partially eclipsed Sun isn’t going to permanently damage your eyes, any more than a glimpse of the Sun at any other time would, as long as you don’t stare at it. Not true. First, it’s total light input that causes pain and motivates you to look away, but it’s local _intensity_ that causes damage. During a partial eclipse, total light is reduced to tolerable levels, but the intensity of the sliver of the sun remaining is the same as an uneclipsed sun. People tend to burn a sliver into their retinas during partial phases. Also, damage is mitigated by the eye’s iris closing down. That is another thing that is governed by total light and not local intensity. A glimpse of a full sun closes down the iris - an eclipsed sun, less so. ---
**Author:** ![flex727](https://avatars.discourse-cdn.com/v4/letter/f/258eb7/32.png) [@flex727](https://boards.straightdope.com/u/flex727)\ **Post date:** [August 8, 2006, 1:27am UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/10 "2006-08-08T01:27:01Z")
> [@Anne Neville](#): > > It’s not UV radiation that causes retinal burns- it’s infrared. > > The red color of the Sun at sunset is caused by blue light being scattered through the atmosphere- short wavelengths are scattered more than long ones. It’s true that you would get less UV at sunrise or sunset, but not less infrared, and infrared is what causes retinal burns. > > I personally would not deliberately stare at the Sun at any time without proper eye protection. Agreed, but just want to point out that, while the IR may be scattered less, it’s certainly attenuated substantially by traversing a much longer path through the atmosphere. It’s obvious that noonday sun feels hotter on your skin than at sunset. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [August 8, 2006, 9:28pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/11 "2006-08-08T21:28:47Z")
> [@myrnajean](#): > > I’ve always heard that you should shut the cover on a copier machine before pressing the start button, or some unknown damage would happen to your eyes, I’ve done that, when I had to copy odd-sized pages. It’s certainly a very bright light, and does make your eyes hurt. But no permanent damage. The worst I’ve ever seen was getting a bad headache if you had to do a lot of such copies. ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [August 9, 2006, 12:56am UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/12 "2006-08-09T00:56:06Z")
> [@myrnajean](#): > > I’ve always heard that you should shut the cover on a copier machine before pressing the start button, or some unknown damage would happen to your eyes I used to tell people that the light from a copier would give them cancer, plus, it wastes valuable toner. It’s not true, except the toner part, but toner costs money. ---
**Author:** ![rocking\_chair](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rocking_chair/32/2918_2.png) [@rocking\_chair](https://boards.straightdope.com/u/rocking_chair)\ **Post date:** [August 9, 2006, 1:26am UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/13 "2006-08-09T01:26:54Z")
the older copiers with the high intensive flash would give some people trouble. not perm. trouble, just some odd blind spots. if you spent hours copying stuff that was rather small or not able to mask out most of the glass with the lid up, people would get dizzy and quezy. one fellow i know couldn’t move his head after 4 hours of copying wee books. if he did not keep his head very straight and square, he would just collapse. him we took to hospital. few days off, and no more copier duty. he is about as normal as he can be. no eye problems. ---
**Author:** ![Aton11](https://avatars.discourse-cdn.com/v4/letter/a/c2a13f/32.png) [@Aton11](https://boards.straightdope.com/u/Aton11)\ **Post date:** [August 10, 2006, 9:54pm UTC](https://boards.straightdope.com/t/youll-burn-your-eyes-out/367720/14 "2006-08-10T21:54:46Z")
[Thank you for your response … I won’t be staring at the sun at dawn or dusk anytime soon!