Summer arrives this Saturday… on Mars! The season will be six months instead of three, thanks to the planet’s two year orbit. Space medical experts discover that shift in bodily fluids in microgravity environment may be why some Astronauts suffer vision changes on orbit – fluid pressure on eye – near- and far-sightedness; may cause increase in intracranial pressure as well. Studies now being done both on orbit and on the ground to gather data to determine exactly what, to what extent and recovery. Venus bright and well positioned in pre-dawn sky now. Jupiter at night.
February 10, 2014
[Dave Heller] It turns out eyeing a possible manned mission to Mars may not be easy on the eyes. Joining me with 20/20 insight is Derrick Pitts, chief astronomer at the Franklin Institute. Derrick, we’re learning more about the rigors of what would be an eight-month long one way trip to the red planet.
[Derrick Pitts] Yes we are, and it has to do with our vision and something that we’ve learned without even having to do an eight month trip. It’s coming across in just a few months on board International Space Station: We’re finding that astronauts who spend time in micro-gravity environments are having vision distortions. And the vision distortions come in the form of increased near-sightedness or increased far-sightedness and the question has been how has this been possible, why has this come up? Some medical specialists are beginning to suspect that it has to do with the shift in bodily fluids in a micro-gravity environment. What happens is the fluids, including your blood, tends to collect in the upper portion of your body, or concentrate in the upper portion of your body, so that your lower limbs don’t have as much fluid volume as the upper portion of your body does. So this results in the puffy face appearance of astronauts occasionally, or their sense of having a severe head cold where they feel congested quite often, and it’s due to the shift in bodily fluids. Well, the medical specialists are beginning to see a couple of interesting things. One is fluid pressure on the back of the eye causing the retinal area of the eye to distort, and that may be causing this change in vision. But they’re also beginning to suspect that there may also be inter-cranial pressures — Increased fluid pressure on the brain.
Do the symptoms resolve after astronauts come back to Earth?
Yeah, that’s a really great question. For most of the abnormalities that astronauts suffer while on orbit, particularly the loss in bone mass and the loss of muscle mass, those things do come back once astronauts return. We don’t really know enough just yet to say what period of time is required for the eye problems to clear up. Although, in some astronauts it seems to have been taking longer once they return than they expected it would take. So there could be some very long-term effects that really have to be carefully considered once we start thinking about taking this very long journey in our solar system.
Astronaut Chris Hadfield describes how eyesight is affected by weightlessness and demonstrates the ultrasound technique use in space.