Date:20 March 2012
The view from orbit is amazing. But your vision in space – well, not so much.
Researchers know that long-duration space travel causes bone loss and weakened muscles. But new studies show that it also creates vision problems.
Medical experts suspect that fluid shifting to the head causes a rise in pressure around the optic nerve at the back of the eye. This pressure pushes the retina forward and causes farsightedness.
For the past 20 years, Nasa has been sending astronauts up with one or more pairs of “space-anticipation glasses”, which have amped-up power, to wear as their sight declined. These kinds of glasses are also available for Earth dwellers whose eyes have lost the ability to refocus from far to near. Superfocus specs have a slider that wearers use to adjust the prescription.
Every shuttle mission launched in 2011 had Superfocus glasses on board, and the glasses are now kept in stock on the International Space Station. – Stephanie Warren
Inner lens: has a membrane filled with clear fluid.
Slider: pushes the transparent fluid to change the shape of the flexible lens, shifting the focus.
Front lens: holds the wearer’s distance prescription.