To the list of health-related problems caused by exposure to microgravity, including bone loss and the effects of radiation, we must now add deterioration of visual acuity. The problem may be related to increased cerebrospinal fluid pressure, an issue not easily resolved by stationary biking and resistance training. How serious the vision loss might be, as well as whether it stabilizes over time, remains to be determined.
Artificial gravity (e.g., attained by rotating the habitation portion of the interplanetary vehicle) might help address this, but the current plans for the Mars One transit vehicle do not involve such an arrangement. Then again, that could change. I guess we’ll see.
(via space.com — the piece is by Michael D Wall, whom I met once in a bar in San Francisco)
Life on Mars 
I know it may seem simple… but could it be just from the fact that the people on a space station never look into the far distance and their eyes just get weak the same as people that work in cubicles on computers and never look off into the distance too?
Maybe, but the etiology sounds really different than screen-related eye strain (see excerpt from the linked article below). The thing that happens in micro-g makes me think of glaucoma, but in reverse.
> researchers think these eye problems stem primarily from an increase in pressure inside the skull. Cerebrospinal fluid flows into the head more in space than it does on Earth, where gravity pulls it down toward the lower body. “That increased pressure of cerebrospinal fluid, which surrounds the brain, works its way down the sheath of the optic nerve and pushes on the back of the eyeball,”
I am a Mars enthusiast who actually has this vision issue but unfortuantly, here on Earth 😉
It’s non life threatening but can result in blindness. It is usually treated with a drug called Diamox which reduces
the amount of cerbro spinal fluid the body generates.
One interesting note is that a swollen optic nerve look a lot like Mars.
http://t.co/ZwfBqYho0Y
You are right, now that I have looked into it more as well, my first comment doesn’t make any sense.
no lens distortion sec to micrograv?
I haven’t heard anything about that. If our lenses were shaped by gravity, it seems like we could apprehend that by changing the orientation of our eyes in a gravity field.