7 ms·

The syndrome impairing astronauts’ eyesight

120 points by markmassie 10y ago

andrewtbham 10y ago
It will not prevent travel to Mars. It's effects can likely be countered. Perhaps by artificial gravity. https://en.wikipedia.org/wiki/Artificial_gravity https://en.wikipedia.org/wiki/Artificial_gravity
- PhantomGremlin 10y ago
  Not everyone is ready to admit it yet, but IMO there is no long term future for us in space without something like artificial gravity. I remember back in the 1970s one of the Skylab astronauts came to my college to give a talk. I had read about some problems, so I asked him about the effects of prolonged weightlessness. He was very dismissive, he vehemently denied that there could be any problems at all. As they say, denial isn't just a river in Egypt. And the denial has been going on for many many decades.
  - trentmb 10y ago
    > He was very dismissive, he vehemently denied that there could be any problems at all. We exist as we do because of the pressures our environment exhibits on us (e.g. gravity)- outside of hubris I can't imagine why folks would think weightlessness would have zero impact.
    - hoorayimhelping 10y ago
      >We exist as we do because of the pressures our environment exhibits on us (e.g. gravity)- outside of hubris I can't imagine why folks would think weightlessness would have zero impact. Skylab 2, 3 and 4 specifically tried to study the effects of space habitation on the human body. I seem to remember reading that the later Skylab crews were considered to be in better health when they came back than when they left. Even though it was early, it could explain the dismissiveness. The data at the time might have made it seem that we'd figured it out already.
  - gizmo686 10y ago
    I am not aware of research on how much gravity is needed to maintain a healthy environment. For example, it is possible that an body as light as Pluto (with only .06 Gs) would offset the majority of the effects of low gravity. If this is the case, then permantant bases on Moons/Planets would face little issues from micro-gravity concerns. If humans require closer to 1G to remain healthy, then these bases become more difficult. We have already demonstrated that humans can stay in space for over a year while remaining relativly healthy. Further, we can achieve artificial "gravity" with centrifugal force if we needed to. Additionally, we could also attempt to solve the problem through medical science, and treat the effects of micro-gravity instead of outright preventing it.
    - stuff4ben 10y ago
      That's a great point. Makes me wonder why we're not getting that moon base setup. Seems like a natural first step prior to colonizing Mars. Learn how to survive on the Moon, take that knowledge and apply to Mars.
  - jerf 10y ago
    Artificial gravity is easy. You "just" spin things. The tricky bit is being able to launch enough mass to build something safe and comfortable to spin; there's a limit to how small you can make your spinning habitat before the difference between "centrifugal force" and gravity is too pronounced for our long term comfort. That's part of why making it cheaper to launch per unit mass is so important. If we could put ten times the mass in space for the same price, the ISS would probably look quite different. I'm of the same opinion as you in general; what spending years in zero-g has proved is that it's not long-term viable. There's too many ways in which it is not viable to expect us to be able to fix all of them, when indeed it's not clear we can fix any of them with drugs or anything short of massive genetic engineering. We don't know how much gravity is necessary, though I'm inclined to guess closer to .5G than .05G. Once you get enough mass in space, though, that's not really that difficult.
    - jfoutz 10y ago
      Two skylabs and a really long rope seems pretty achievable. The full wheel from 60's sci fi looks very cool, but two weights on opposite sides of a string seems so much simpler.
      - lttlrck 10y ago
        This idea is used in Seveneves https://en.m.wikipedia.org/wiki/Seveneves https://en.m.wikipedia.org/wiki/Seveneves
    - hoorayimhelping 10y ago
      >The tricky bit is being able to launch enough mass to build something safe and comfortable to spin; Is it? I might have a completely busted mental model, but I thought you only need a module-sized mass on one end of a rod the length of things we've already assembled in space (e.g. an ISS truss) and a motor to spin it.
      - jerf 10y ago
        It gets complicated, and the mass budget starts going up fast, if you want other things to be able to dock to it. Two space stations on the opposite side of a long rope (per the other reply) is also not a very compelling story to tell to Congress when you have to admit that astronauts won't be able to travel between those two space stations to speak of, unless, again, you really up the mass budget. We're space-poor. It's just too darned expensive. Even relatively simple designs are out of our reach right now, if you have to manifest them in real designs with real safety margins and real practical applications, such as being dockable.
  - vixen99 10y ago
    'no long term future for us in space without something like artificial gravity.' and without an answer to the radiation problem. http://www.wired.com/2014/04/radiation-risk-iss-mars/ http://www.wired.com/2014/04/radiation-risk-iss-mars/
  - mkstowegnv 10y ago
    Except for Venus with .9 Earth gravity and where colonies floating above the clouds have many advantages over, and may be no more difficult to create than, colonization schemes for Mars or anywhere else in space/away from Earth. https://en.wikipedia.org/wiki/Colonization_of_Venus#Advantages https://en.wikipedia.org/wiki/Colonization_of_Venus#Advantag...
- kilroy123 10y ago
  I really don't understand why NASA has never done experiments for creating gravity in space. We know how we could make it work.
  - gpm 10y ago
    They have, technically, on Gemini 11 they produced 0.00015g of "gravity". https://en.wikipedia.org/wiki/Gemini_11 https://en.wikipedia.org/wiki/Gemini_11 I do wish they would try again with modern technology.
- wolf550e 10y ago
  Yes, Zubrin has been advocating for this since 1990. https://www.youtube.com/watch?v=3UChuIqIKF4&t=1722 https://www.youtube.com/watch?v=3UChuIqIKF4&t=1722 His explanation about the real situation with NASA and why the human spaceflight program has not accomplished anything is extremely disheartening. https://www.youtube.com/watch?v=3UChuIqIKF4&t=417 https://www.youtube.com/watch?v=3UChuIqIKF4&t=417
  - imaginenore 10y ago
    The real problem is you need to deliver so much material to orbit to create artificial gravity (a rotating space station) it's very expensive. We could create a simple rotating system with two pods connected by a long cable, but then it's not easy to dock to it, and there are balancing issues.
    - ekianjo 10y ago
      That should get much cheaper once spacex gets things right.
      - akiselev 10y ago
        Even if SpaceX made the launch costs a hundred times cheaper than the shuttle, it would still cost over $500 million and that would only launch a tiny fraction of the mass needed for a full artifical gravity space station. The estimated cost of the International Space Station so far is over $100 billion not including launch costs so even if another company cut costs there by a factor of ten, thats $10 billion, again a small fraction of what you would need. You can cut out bureaucracy and save money with a private company instead of government agencies but this would be a one off design made for space habitation so there really isn't much room to drastically reduce costs. If you want this thing to also travel around the solar system, you'd need to complicate the design even more because the ISS is solar based and has only orbital correction propulsion which is much cheaper. It's possible but I don't think it will be economical or practical for a long time.
        10y ago
- sarreph 10y ago
  It may not prevent travel to Mars (for example, on a centrifugal space station), but considering gravity on Mars is 62% lower than here on Earth, I would postulate without some kind of gravity manipulation we are yet to develop (unless we have the energy to build centrifugal colonies on land) then manned missions on Mars would suffer a similar fate.
  - Snowdax 10y ago
    Until relativity and the standard model can be merged and we can figure out a cause and effect between gravity and other fundamental forces and figure out who to trigger gravity with an electrical switch for example gravity manipulation is not going to happen for quite some time. We'll probably just take the risk and go to Mars and suffer the health consequences.
    - wtetzner 10y ago
      > We'll probably just take the risk and go to Mars and suffer the health consequences. Or find a way to treat the problems directly, rather than avoid them using artificial gravity.
tines 10y ago
So what I'm hearing is that we should send myopic people into space to fix their vision!
- fractx 10y ago
  Only in theory. The induced hyperopic shift from axial length reduction of the eyeball would likely be reversible after the patient's intracranial pressure is brought back down under control. Moreover it is nearly impossible to find the sweet spot for just the right amount of hyperopic shift to negate preexisting myopia, not to mention that astigmatism cannot be corrected this way. The more important and irreversible side effects include elevated intraocular pressure leading to glaucoma risks, and poor blood perfusion to the optic nerve leading to non-arteritic anterior ischemic optic neuritis (as mentioned in the article inflamed optic nerve), both result in permanent loss in parts of the visual field. The choroidal folds are unlikely to cause any change in vision though. So all factors considered, it's really not a great way to correct myopia.
meowface 10y ago
Could overhydration cause similar eye issues, since it also increases intracranial pressure?
wizardhat 10y ago
Studies going as far back as the 80s show that people in submarines develop myopia: http://www.ncbi.nlm.nih.gov/pubmed/7457562 http://www.ncbi.nlm.nih.gov/pubmed/7457562 The leading theory is that being in a confined space causes the eye to adapt to viewing things up close rather than at a distance.
- mtreis86 10y ago
  Anecdote: I saw an article about Native Americans, using a technique of quickly focusing from near to far and back as a means to increase their eyesight range, when I was around twelve years old. Called Eagle Eyes, or something. I have been practicing regularly for eighteen years now, and my eyesight has only improved. I have been looking at computers and books at least a third of my time since. Am I actively preventing myopia? Interesting.
  - whuuu3 10y ago
    That's really interesting. What were your prescriptions before/after?
    - mtreis86 10y ago
      I was 20/20 in both eyes before, 20/15 in one and 20/10 in the other now. The last measurement was two years ago.
      - Terretta 10y ago
        Are you over 40-45, or under?
  - pivo 10y ago
    Years ago my optometrist suggested I do this exercise. I've been doing it at regular intervals throughout the day for the last 10 years or so. Can't say my eyesight has improved but maybe it's prevented it from getting worse.
Gracana 10y ago
"The only proven methods of measuring intracranial pressure are invasive: the spinal tap or drilling a hole into the skull." Sounds like we need to test/prove something new. I did some searching for a wireless intracranial pressure sensor and didn't find anything, but I bet you could make one. The sensor could be a pair of capacitor plates on the inside of a sealed cavity in a flexible material, with an antenna attached, such that the capacitance changes as the cavity is squeezed by the pressure around it. To make a measurement, you'd use an external antenna to hit the sensor antenna with an impulse, which would cause it to ring at a frequency proportional to the pressure it's monitoring. Very simple, no batteries, could be made very small... [edit] Oh hey, they mention implanted devices. I guess I should have finished reading the article before posting.
datenwolf 10y ago
Damn, as a guy in OCT research, working with the ATM most advanced OCT imaging systems there are (which we develop ourself) it's been itching me to get one of our systems up there for research. There's currently a Heidelberg OCT on board the ISS, but this thing can do only 2D scans in high resolution. And with our stuff we can do 3D scans in high resolution and even markerless angiography.
Symmetry 10y ago
Gosh, if only we'd been willing to pay for research to tell us if this effect arises in the low gravity of Mars or the Moon as well as in microgravity. https://en.wikipedia.org/wiki/Centrifuge_Accommodations_Module https://en.wikipedia.org/wiki/Centrifuge_Accommodations_Modu...
ISL 10y ago
Though this comment comes days late -- if the effect cannot be countered, perhaps sending farsighted astronauts to Mars would allow them to arrive with fully-corrected vision.

120 points by markmassie 10y ago

It will not prevent travel to Mars. It's effects can likely be countered. Perhaps by artificial gravity. https://en.wikipedia.org/wiki/Artificial_gravity https://en.wikipedia.org/wiki/Artificial_gravity

PhantomGremlin 10y ago
Not everyone is ready to admit it yet, but IMO there is no long term future for us in space without something like artificial gravity. I remember back in the 1970s one of the Skylab astronauts came to my college to give a talk. I had read about some problems, so I asked him about the effects of prolonged weightlessness. He was very dismissive, he vehemently denied that there could be any problems at all. As they say, denial isn't just a river in Egypt. And the denial has been going on for many many decades.
- trentmb 10y ago
  > He was very dismissive, he vehemently denied that there could be any problems at all. We exist as we do because of the pressures our environment exhibits on us (e.g. gravity)- outside of hubris I can't imagine why folks would think weightlessness would have zero impact.
  - hoorayimhelping 10y ago
    >We exist as we do because of the pressures our environment exhibits on us (e.g. gravity)- outside of hubris I can't imagine why folks would think weightlessness would have zero impact. Skylab 2, 3 and 4 specifically tried to study the effects of space habitation on the human body. I seem to remember reading that the later Skylab crews were considered to be in better health when they came back than when they left. Even though it was early, it could explain the dismissiveness. The data at the time might have made it seem that we'd figured it out already.
- gizmo686 10y ago
  I am not aware of research on how much gravity is needed to maintain a healthy environment. For example, it is possible that an body as light as Pluto (with only .06 Gs) would offset the majority of the effects of low gravity. If this is the case, then permantant bases on Moons/Planets would face little issues from micro-gravity concerns. If humans require closer to 1G to remain healthy, then these bases become more difficult. We have already demonstrated that humans can stay in space for over a year while remaining relativly healthy. Further, we can achieve artificial "gravity" with centrifugal force if we needed to. Additionally, we could also attempt to solve the problem through medical science, and treat the effects of micro-gravity instead of outright preventing it.
  - stuff4ben 10y ago
    That's a great point. Makes me wonder why we're not getting that moon base setup. Seems like a natural first step prior to colonizing Mars. Learn how to survive on the Moon, take that knowledge and apply to Mars.
- jerf 10y ago
  Artificial gravity is easy. You "just" spin things. The tricky bit is being able to launch enough mass to build something safe and comfortable to spin; there's a limit to how small you can make your spinning habitat before the difference between "centrifugal force" and gravity is too pronounced for our long term comfort. That's part of why making it cheaper to launch per unit mass is so important. If we could put ten times the mass in space for the same price, the ISS would probably look quite different. I'm of the same opinion as you in general; what spending years in zero-g has proved is that it's not long-term viable. There's too many ways in which it is not viable to expect us to be able to fix all of them, when indeed it's not clear we can fix any of them with drugs or anything short of massive genetic engineering. We don't know how much gravity is necessary, though I'm inclined to guess closer to .5G than .05G. Once you get enough mass in space, though, that's not really that difficult.
  - jfoutz 10y ago
    Two skylabs and a really long rope seems pretty achievable. The full wheel from 60's sci fi looks very cool, but two weights on opposite sides of a string seems so much simpler.
    - lttlrck 10y ago
      This idea is used in Seveneves https://en.m.wikipedia.org/wiki/Seveneves https://en.m.wikipedia.org/wiki/Seveneves
  - hoorayimhelping 10y ago
    >The tricky bit is being able to launch enough mass to build something safe and comfortable to spin; Is it? I might have a completely busted mental model, but I thought you only need a module-sized mass on one end of a rod the length of things we've already assembled in space (e.g. an ISS truss) and a motor to spin it.
    - jerf 10y ago
      It gets complicated, and the mass budget starts going up fast, if you want other things to be able to dock to it. Two space stations on the opposite side of a long rope (per the other reply) is also not a very compelling story to tell to Congress when you have to admit that astronauts won't be able to travel between those two space stations to speak of, unless, again, you really up the mass budget. We're space-poor. It's just too darned expensive. Even relatively simple designs are out of our reach right now, if you have to manifest them in real designs with real safety margins and real practical applications, such as being dockable.
- vixen99 10y ago
  'no long term future for us in space without something like artificial gravity.' and without an answer to the radiation problem. http://www.wired.com/2014/04/radiation-risk-iss-mars/ http://www.wired.com/2014/04/radiation-risk-iss-mars/
- mkstowegnv 10y ago
  Except for Venus with .9 Earth gravity and where colonies floating above the clouds have many advantages over, and may be no more difficult to create than, colonization schemes for Mars or anywhere else in space/away from Earth. https://en.wikipedia.org/wiki/Colonization_of_Venus#Advantages https://en.wikipedia.org/wiki/Colonization_of_Venus#Advantag...
kilroy123 10y ago
I really don't understand why NASA has never done experiments for creating gravity in space. We know how we could make it work.
- gpm 10y ago
  They have, technically, on Gemini 11 they produced 0.00015g of "gravity". https://en.wikipedia.org/wiki/Gemini_11 https://en.wikipedia.org/wiki/Gemini_11 I do wish they would try again with modern technology.
wolf550e 10y ago
Yes, Zubrin has been advocating for this since 1990. https://www.youtube.com/watch?v=3UChuIqIKF4&t=1722 https://www.youtube.com/watch?v=3UChuIqIKF4&t=1722 His explanation about the real situation with NASA and why the human spaceflight program has not accomplished anything is extremely disheartening. https://www.youtube.com/watch?v=3UChuIqIKF4&t=417 https://www.youtube.com/watch?v=3UChuIqIKF4&t=417
- imaginenore 10y ago
  The real problem is you need to deliver so much material to orbit to create artificial gravity (a rotating space station) it's very expensive. We could create a simple rotating system with two pods connected by a long cable, but then it's not easy to dock to it, and there are balancing issues.
  - ekianjo 10y ago
    That should get much cheaper once spacex gets things right.
    - akiselev 10y ago
      Even if SpaceX made the launch costs a hundred times cheaper than the shuttle, it would still cost over $500 million and that would only launch a tiny fraction of the mass needed for a full artifical gravity space station. The estimated cost of the International Space Station so far is over $100 billion not including launch costs so even if another company cut costs there by a factor of ten, thats $10 billion, again a small fraction of what you would need. You can cut out bureaucracy and save money with a private company instead of government agencies but this would be a one off design made for space habitation so there really isn't much room to drastically reduce costs. If you want this thing to also travel around the solar system, you'd need to complicate the design even more because the ISS is solar based and has only orbital correction propulsion which is much cheaper. It's possible but I don't think it will be economical or practical for a long time.
      - 10y ago
sarreph 10y ago
It may not prevent travel to Mars (for example, on a centrifugal space station), but considering gravity on Mars is 62% lower than here on Earth, I would postulate without some kind of gravity manipulation we are yet to develop (unless we have the energy to build centrifugal colonies on land) then manned missions on Mars would suffer a similar fate.
- Snowdax 10y ago
  Until relativity and the standard model can be merged and we can figure out a cause and effect between gravity and other fundamental forces and figure out who to trigger gravity with an electrical switch for example gravity manipulation is not going to happen for quite some time. We'll probably just take the risk and go to Mars and suffer the health consequences.
  - wtetzner 10y ago
    > We'll probably just take the risk and go to Mars and suffer the health consequences. Or find a way to treat the problems directly, rather than avoid them using artificial gravity.

tines 10y ago

So what I'm hearing is that we should send myopic people into space to fix their vision!

fractx 10y ago
Only in theory. The induced hyperopic shift from axial length reduction of the eyeball would likely be reversible after the patient's intracranial pressure is brought back down under control. Moreover it is nearly impossible to find the sweet spot for just the right amount of hyperopic shift to negate preexisting myopia, not to mention that astigmatism cannot be corrected this way. The more important and irreversible side effects include elevated intraocular pressure leading to glaucoma risks, and poor blood perfusion to the optic nerve leading to non-arteritic anterior ischemic optic neuritis (as mentioned in the article inflamed optic nerve), both result in permanent loss in parts of the visual field. The choroidal folds are unlikely to cause any change in vision though. So all factors considered, it's really not a great way to correct myopia.

meowface 10y ago

Could overhydration cause similar eye issues, since it also increases intracranial pressure?

wizardhat 10y ago

Studies going as far back as the 80s show that people in submarines develop myopia: http://www.ncbi.nlm.nih.gov/pubmed/7457562 http://www.ncbi.nlm.nih.gov/pubmed/7457562 The leading theory is that being in a confined space causes the eye to adapt to viewing things up close rather than at a distance.

mtreis86 10y ago
Anecdote: I saw an article about Native Americans, using a technique of quickly focusing from near to far and back as a means to increase their eyesight range, when I was around twelve years old. Called Eagle Eyes, or something. I have been practicing regularly for eighteen years now, and my eyesight has only improved. I have been looking at computers and books at least a third of my time since. Am I actively preventing myopia? Interesting.
- whuuu3 10y ago
  That's really interesting. What were your prescriptions before/after?
  - mtreis86 10y ago
    I was 20/20 in both eyes before, 20/15 in one and 20/10 in the other now. The last measurement was two years ago.
    - Terretta 10y ago
      Are you over 40-45, or under?
- pivo 10y ago
  Years ago my optometrist suggested I do this exercise. I've been doing it at regular intervals throughout the day for the last 10 years or so. Can't say my eyesight has improved but maybe it's prevented it from getting worse.

Gracana 10y ago

"The only proven methods of measuring intracranial pressure are invasive: the spinal tap or drilling a hole into the skull." Sounds like we need to test/prove something new. I did some searching for a wireless intracranial pressure sensor and didn't find anything, but I bet you could make one. The sensor could be a pair of capacitor plates on the inside of a sealed cavity in a flexible material, with an antenna attached, such that the capacitance changes as the cavity is squeezed by the pressure around it. To make a measurement, you'd use an external antenna to hit the sensor antenna with an impulse, which would cause it to ring at a frequency proportional to the pressure it's monitoring. Very simple, no batteries, could be made very small... [edit] Oh hey, they mention implanted devices. I guess I should have finished reading the article before posting.

datenwolf 10y ago

Damn, as a guy in OCT research, working with the ATM most advanced OCT imaging systems there are (which we develop ourself) it's been itching me to get one of our systems up there for research. There's currently a Heidelberg OCT on board the ISS, but this thing can do only 2D scans in high resolution. And with our stuff we can do 3D scans in high resolution and even markerless angiography.

Symmetry 10y ago

Gosh, if only we'd been willing to pay for research to tell us if this effect arises in the low gravity of Mars or the Moon as well as in microgravity. https://en.wikipedia.org/wiki/Centrifuge_Accommodations_Module https://en.wikipedia.org/wiki/Centrifuge_Accommodations_Modu...

ISL 10y ago

Though this comment comes days late -- if the effect cannot be countered, perhaps sending farsighted astronauts to Mars would allow them to arrive with fully-corrected vision.