And what keeps them from freezing before that temperature?
This post got me wondering:
Assume no eye protection.
Corollary 1: Is there a temperature at which our eyeballs will freeze before we hit hypothermia?
Corollary 2: If our eyeballs froze, and we were still conscious, what would be the resultant effect on our vision?
Surely the eyes, containing blood vessels and live tissue as they do, would be kept warm artificially by the body, in the same way the skin and the organs are? In order for your eyes to freeze your body temperature would have to fall so low that you would by definition have hypothermia. I’d hope anyway - otherwise I’ll be worrying about my eyes freezing next time I go out…
Do we get to carry a mirrored shield?
Don’t some seabirds or the like have a specialized artery/vein arrangement in their legs to maintain body temperature? Given how effective that is, I’d say TGP’s point about constant blood flow would either prevent freezing or lead to horrid complications before obtaining eyece cubes.
Can ocular experts describe how much of the eye has blood going through it compared to the overall volume of fluid? Perhaps it can freeze quick enough to block the capillaries and prevent circulation to the eye. Man that’s gonna hurt.
Good point, but assume you weren’t walking around naked. Instead you had the best protection from the weather for the rest of your body, with just your eyes exposed. To borrow a phrase, when would they become eyece cubes and iceplode?
No factual answer, but I’ve been out in -45DEG Celsius weather with some wind (I’m guessing -50 – -55 effective), and altough your eyes will often tear up and those tears will freeze quickly, as long as you clean away this from time to time - no ill effects.
I could see problems if you had extreme cold, a major wind, and deliberately held your eyes wide open for extended periods. But I think it’s natural to squint your eyes down to slits if it’s very windy; your eyelashes help to occlude what littl gap remains, preserving a protected pocket of air in front of your eyeballs.
Your eyeballs are being cooled on their front surface by convection from a gas (air), and warmed from behind by convection and conduction from 98.6-degree liquid. Given the above paragraph and this one, my gut reaction is that it would have to be unnaturally cold out to risk freezing the surface of your eyeballs.
This is fiction, and not an answer to the question, but the novel “The Terror” by Dan Simmons, has a very memorable scene where a character’s eyeballs freeze.
I immediately thought of that when I saw this thread.
Even so, I think you’d suffer frostbitten corneas at worst - for the eyeball itself to freeze, I think the whole outer surface of the head has to be doing the same.
What’s ‘artificial’ about it? 
What, you don’t know? Oh man! Here, put on these glasses.
I hope y’all will pardon the hijack, but this reminded me of something I read in a book on Antarctica. At some extremely low temperature (around -60 F, perhaps?), just breathing the air will cause you to eventually die of hypothermia, no matter how warmly you’re dressed.
No!
Although posters describe experiences in extremely cold weather, and still have their eyeballs intact, you always hear weatherpeople tell you not to go outside with exposed skin when it’s, say, below zero, due to the risk of frostbite. But they never tell you to cover your eyes, and it seems that the eyes would be more prone to freezing than skin since they have a large water content (my speculation only).
So if they don’t freeze, or at least get damaged, why not, if my fingers would get frostbite without gloves pretty quickly in that kind of cold?
Cuz your eyeballs are pretty well protected. They are positioned in depressions in your face, and are in little pockets formed by your eyelids. Your eyelashes help keep the wind from blasting away the tiny pocket of above-freezing air immediately in front of each eyeball. You blink on a regular basis, wiping the surface of your eyes with a warm eyelid (your eyelids, when not shut, are retracted behind your eyebrows). The surface of your eye is a (approximately) flat region, not a narrow appendage like your fingers.
Icy what you did there.
Because your body will limit the amount of blood sent to the extremities in an effort to keep your internal organs warm. Frostbite is better than death. Most of the stuff in your head though is pretty important so it is not subject to the restriction of blood circulation.
My wife gives me that icy cold stare alot. Ill ask her!
Interesting. This is relevant, because it at least puts a lower bound to the temperature at which MoodIndigo1 can go for a walk.
Can anyone find a ceyete for this? If this is true, and we hit hypothermia by just breathing the air, regardless of clothing cover, then it appears from responses in this thread that we won’t make eyece cubes before we deye of eyepothermia.
And no one seems to have taken a stab at this part of the question (assume a hypothetical scenario, since it seems unlikely that we’ll be conscious in such a state):
Corollary 2: If our eyeballs froze, and we were still conscious, what would be the resultant effect on our vision?
Assuming they froze gradually from the front to the back…
Partial loss of vision similar to a cataract
Visual phosphene-type disturbances caused by the extra pressure on the retina as the eyece expands
Total loss of sight once the retina starts to freeze. In the absence of proper input, the brain might still register some phenomena that appear visual, but with no particular correlation to the real world.
notice that you can still, sort of, see if you squint your eyes, thus reducing their exposed surface and putting the eyelashes in front of it. Presumably if you have narrow eyes like people from Mongolia (a place with windy cold winters) this gets easier to do.
That being said, temperatures above -50C were considered sufficiently warm to do serious work (not just walking around squinting) in Siberian prison labor camps under Stalin. (For free people the minimal allowed temperature was usually much higher, I think -30C or -35C).
I guess the moral of the story is, our eyes are capable of handling pretty much any temperature found in the regions where humans actually live, even without the eye shape of the northern Asian people.