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I'd like to know if astronauts have been under the effect of Disabling Glare, how easily this could accidentally happen and how long can last if this happen?

Gonzalo Ledezma Torres
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    Once you go blind, whether you are an astronaut or just a human on the Earth's surface, you generally don't regain your sight. – Rory Alsop Aug 17 '20 at 16:42
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    @RoryAlsop It might be also a temporary blindness causing, for example, dangers in common traffic. – peterh Aug 17 '20 at 18:30
  • The atmosphere filters out about a half of the sunlight. – peterh Aug 17 '20 at 18:30
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    @RoryAlsop if one bleaches the photoreceptor molecules with too much visible light then it's only a matter of time before they are removed and replaced with fresh photoreceptors. This is the rationale Feynman use when viewing an atomic bomb detonation through a car window; the glass would remove any dangerous UV and the eye can not transmit thermal IR, leaving only near IR and visible. https://www.realclearscience.com/blog/2016/04/what_its_like_to_actually_see_an_atomic_explosion.html quotes from "Surely You're Joking, Mr. Feynman!": Adventures of a Curious Character – uhoh Aug 17 '20 at 19:04
  • @uhoh, Re, "...leaving only near IR and visible..." You should talk to somebody who works with high-powered, visible-light lasers about whether visible light can harm your eyes or any other part of your body. – Solomon Slow Aug 17 '20 at 19:44
  • I don't understand the question. You can stand on the earth's surface and go blind looking at the sun. –  Aug 17 '20 at 22:47
  • @BenCrowell Blind as been dazzled for more than X amount of time, but knowing that you can recover after that amount of time. Didn't put the context, sorry about that. – Gonzalo Ledezma Torres Aug 17 '20 at 23:52
  • @SolomonSlow sure! I remember talk of the development of a nasty weapon that combined a powerful near IR laser beam with a weak visible laser pointer. The victim would notice and look at a weak spot of visible light from the pointer which would focus the powerful invisible near IR beam to a single spot on the retina where it would concentrate so much power to such a small volume that there would be boiling and catastrophic, horrible trauma. Just for good measure: WHEN USING LASERS, VISIBLE, UV or IR, ALWAYS READ AND UNDERSTAND ALL SAFETY ISSUES AND WEAR THE RIGHT EYE PROTECTION FOR THAT LASER! – uhoh Aug 18 '20 at 00:16
  • @SolomonSlow but addressing the comment "Once you go blind... you generally don't regain your sight" I was simply providing a counterexample where one could experience temporarily, reversible blindness. The atomic detonation, even at the distance that Feynman watched, was an extended source, not a collimated laser beam. It would flood an extended area of the retina with light and would not be focused to a concentrated small point as a collimated beam would be. – uhoh Aug 18 '20 at 00:20
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    Voting to leave the question open and will vote to reopen it if the insta-closers succeed. I think the question is on-topic and can have a science and fact-based answer. There is no reason to quickly block users from an opportunity to post an answer! We have one fact-based answer already, let's continue to allow users to post more! Instead if someone has a good idea how to improve the question, go ahead and edit it or provide a helpful suggestion how to do so! – uhoh Aug 18 '20 at 00:30
  • The atmosphere filters out about a half of the visible sunlight. So, it will be harder than just seeing into the Sun directly from the Earth. But I am not sure about, for example, the UV. – peterh Aug 18 '20 at 05:24
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    You can seriously damage your eyes by looking directly into the sun even when standing on Earth. I fail to see why astronauts wouldn't have it even worse. – Polygnome Aug 18 '20 at 12:21
  • @uhoh's edit helps - referring to temporary blindness, rather than the original post, but it's still a bad question that has nothing to do with Space – Rory Alsop Aug 18 '20 at 15:32
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    I did a new edit. I did some research and I think this non-totally-blindness is called Disabling Glare. – Gonzalo Ledezma Torres Aug 20 '20 at 20:59
  • @GonzaloLedezmaTorres well done! – uhoh Aug 21 '20 at 02:40
  • i only voted to close because of the tantrum above. –  Aug 21 '20 at 10:45
  • The question post seems fine and is being answered well, voting to reopen as promised! If there are issues in comments, flagging for moderator attention is the correct action. Closing prevents other from posting answers. Since we don't know yet what those answers may be, pre-closing to prevent them doesn't seem productive. – uhoh Aug 21 '20 at 13:59

3 Answers3

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Partial answer (written prior to major edit of question):

Not sure about "going blind" but eye damage can occur in as little as 10 seconds. Nor do I know how long it takes to recover from "going blind".

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Most spacecraft windows and spacesuit helmet visors have coatings to prevent transmission of UV. This label refers to the one on the shuttle that didn't.

Reference: Do astronauts have to use sunscreen?

The shuttle Medical Checklist EYE PROBLEMS category does not have an entry for eye damage caused by exposure to UV.

Organic Marble
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  • I wonder if during EVAs the ISS astronauts are required to don any light-reducing shield over their helmets whenever they are in a sunlit area, or if it's completely voluntary, as well as wonder if that a separate question. – uhoh Aug 18 '20 at 00:48
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    Anecdotal comment (and, a data set of one): I found it literally, perhaps even physiologically, impossible to force my naked eyes to within about 20 arc-degrees or so of the sun when viewed through a window...just could not do it. The sun was a demon up there! Dark sunglasses were an absolute must if doing any work that involved looking anywhere near the sun. – Digger Sep 18 '20 at 15:16
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Special requirements in open space are imposed on the transparent part of the suit: protection of eyes and face from active ultraviolet rays, infrared (thermal) rays, should weaken solar radiation in the visible part of the spectrum, while ensuring good visibility at this illumination.

В открытом космосе, за пределами атмосферы, состав солнечного излучения существенно отличается от того, к которому мы привыкли на поверхности Земли. Поэтому особые требования предъявляются к прозрачной части шлема: остекление и светофильтры должны защитить глаза и кожу лица от чрезвычайно активных ультрафиолетовых лучей, от инфракрасных (тепловых) лучей, должны ослабить солнечное излучение в видимой части спектра, обеспечив при этом хорошую видимость при различной освещенности.

Magazine "Science and Life" №6-1978. Space suits.

A. Rumlin
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The major risk to the eye in space is ultraviolet light. This is mostly absorbed by the cornea (which is lucky for deeper ocular structures, but bad for the cornea).

Short, high dose UV exposure (such as welding flash or unprotected exposure to sunlight in space) produces acute damage to the corneal epithelium (the thin surface tissue of the cornea). Because the the epithelium is highly innervated by sensory nerves, this is extremely painful. It is colloquially known as "snow blindness". Fortunately the epithelium rapidly heals (usually within 24hrs) but those affected are usually non-functional for that time due to pain and glare.

Chronic, lower doses of UV (like living in the tropics) can produce damage to the conjunctiva (the thin membrane which covers the white part of the eye). This stimulates the inflamed conjunctiva to grow across the cornea, eventually decreasing vision. If neglected, it can cause blindness. The condition is treated with surgical grafting using conjunctiva from under the upper lid "where the sun don't shine"..

Some of the UV penetrates the cornea and is absorbed by the lens. This accelerates cataract formation. On average, cataracts develop 6 months younger in tropical populations than temperate.

Woody
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  • Looking directly at the Sun focuses light onto the retina causing damage. But I'm guessing the cornea and lens receive potential damage anytime sunlight is directly striking the eye, even if not looking directly at the Sun. I suppose they get the most damage when "pointed" in the direction of the Sun, although that would seem to be the case even if not looking directly at the Sun but just its general direction, like watching an airplane that is say 20 degrees from the Sun. Presumably even just having the Sun in peripheral view might do a small amount of damage to the cornea and lens over time. – Steve Pemberton Nov 09 '23 at 12:02
  • @StevePemberton .. correct. That's why cataracts, pinguecula (damage to the conjunctiva) and pterygium (damage to the cornea) are all more common with chronic sun exposure. There is some evidence that even blue light contributes to macular degeneration. – Woody Nov 09 '23 at 13:31