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[Waspie_Dwarf]

New Findings on Astronaut Vision Loss

www.nasa.gov said:

Could vision changes experienced by astronauts be linked to a vitamin B-12 or folate deficiency? While investigating the vision changes recently identified in astronauts, nutritional assessment data showed similarities to symptoms that occur with vitamin deficiencies, according to a new study published in the March edition of The Journal of Nutrition.

Approximately 20 percent of astronauts living on the International Space Station have reported post-flight vision changes. Previous research, published in the October 2011 issue of Ophthalmology, identified a possible link between the reported vision changes and increased intracranial pressure caused by shifts in bodily fluids from the lower extremities to the upper part if the body, due to microgravity. This may still be part of the problem, but the new study shows there may be other contributing factors. The findings may provide evidence to help understand why some crew members suffer vision-related problems, while others do not.

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[nephilim12]

Loss of vision caused by nutritional deficiency ?
If that were the reason, much of the developing countries having a population severely malnourished would be blind.
Peoples' vision doesn't get affected except if under extreme conditions over a prolonged period of time. And the effects would only be felt after the age of 40 in any case, on a general observation of age groups of most eye patients.
The effects of zero gravity on distribution of intra-cranial fluids may well be the likely cause. In any case, the cause-effect is a subject to be studied at a microscopic level with all possibilities considered.
On the sidelines, there are some who speculate that continued exposure to harmful solar radiation at such altitudes and in space may be one of the reasons for optic-nerve damage which eventually affects vision adversely.
But like I said, all possibilities to be considered and shortlisted for a lasting solution.
We owe that much to our boys who despite knowing the risks involved, volunteer to assume positions of responsibilities that an astronaut takes on.

[Waspie_Dwarf]

nephilim12, on 30 May 2012 - 04:13 PM, said:

Loss of vision caused by nutritional deficiency ?
If that were the reason, much of the developing countries having a population severely malnourished would be blind.
Peoples' vision doesn't get affected except if under extreme conditions over a prolonged period of time.

Did you read the full article? If so you seem to have missed this:

Quote

With nutritional deficiencies ruled out, researchers began considering the possibility that polymorphisms, which may be part of the one-carbon pathway, could be causing the vision changes.

(My emphasis).

[Render]

nephilim12, on 30 May 2012 - 04:13 PM, said:

Loss of vision caused by nutritional deficiency ?
If that were the reason, much of the developing countries having a population severely malnourished would be blind.
Peoples' vision doesn't get affected except if under extreme conditions over a prolonged period of time. And the effects would only be felt after the age of 40 in any case, on a general observation of age groups of most eye patients.

a big part of the malnourished population DOES suffer from nightblindness, some from complete blindness. And it certainly doesn't take 40 years.
Never heard of the phrase that carrots are good for your eyes?