We've been space for over forty years but NASA was totally unprepared for a recent finding.  Long term stints in space may cause damage to astronaut's eyesight.

Even the longest of Space Shuttle missions were relatively short jaunts into near earth orbit.  The biggest lesson learned was there was so much more to know.  One of the dangers of long term space flight has been exposed thanks to constant habitation of the International Space Station.

The NASA study found those spending more than a month in space were more likely to suffer from intracranial hypertension.  It occurs when pressure builds in the skull.  The pressure causes a slight deformity in the back of the eyeball.  The effects were not always bad, in some cases correcting some astronaut's vision.

While many see this finding as a potential limiter in long term space travel it actually represents opportunity.   While we may never conquer space in our lifetime it's through these kinds of findings and overcoming them that we set the stage for those who will.

For more see this source article.