Space Vision   
       
   Nov. 17, 2015: Traveling in space has many odd effects on the human body. One   
   of the strangest has to do with vision.   
       
   After spending some time on the International Space Station, many astronauts   
   discover that they cannot see as well as they do on Earth.  The effect is so   
   well known that members of the crew routinely pack "space glasses" to correct   
   their vision in orbit.   
       
   https://www.youtube.com/watch?v=xtq3b_HYg9w#t=11   
       
   Many astronauts report a blurring of their eyesight in microgravity.   
   Researchers are trying to get to the bottom of this phenomenon before   
   astronauts travel to Mars and beyond.   
       
   Researchers still aren't sure what causes the problem, but they would like to   
   solve it before humans travel beyond low-Earth orbit. A trip to Mars could   
   take at least three years -- five times as long as a mission to the station.   
   So it's important to learn about the adverse effects of microgravity on vision   
   and develop ways to counter them.   
       
   Christian Otto of the Universities Space Research Association in Houston,   
   Texas, is one of the researchers trying to get a clearer understanding of   
   "space vision." He is the Principal Investigator of the Ocular Health study   
   now underway on the space station.   
       
   An accomplished off-road triathlete with an interest in human performance in   
   extreme environments, Otto is well-suited to this PI role. He once toted an   
   ultrasound machine up Mount Everest to study the effects of oxygen deprivation   
   on intracranial pressure. Now, with the Ocular Health study, he's remotely   
   conducting similar tests on astronauts.   
       
   "Testing astronauts before, during, and after their missions to the station   
   shows us their status preflight and helps us identify changes that result from   
   the environment and microgravity on the station," explains Otto.   
       
   On the space station, the body's fluids, particularly the blood supply, shift   
   toward the head much like what happens on Earth when you lie down. Therefore,   
   it is hypothesized that the pressure inside the skull increases. That increase   
   in intracranial pressure is believed to be transmitted to the eye and optic   
   nerve, leading to changes in eye structure and visual acuity.   
       
   Optic Disc Edema (ODE) -- swelling of the optic disc -- is the most critical   
   change. If it persists, it can lead to a loss of peripheral vision and   
   eventual blindness. Astronauts have experienced only mild ODE to date, but no   
   one knows how severe it could become on a Mars expedition.   
       
   "Data from this study will help researchers develop countermeasures for and   
   reduce susceptibility to issues like ODE," says Otto. "It will help us develop   
   targeted treatments to prevent problems."   
       
   Adding preliminary data from the Ocular Health study to data from previous   
   Vision Impairment and Intracranial Pressure (VIIP) studies, Otto and his team   
   have made some interesting discoveries.   
       
   "Around 70% of 33 International Space Station crewperson subjects have   
   experienced mild VIIP, and we are finding that men are affected about twice as   
   severely as women.   
       
   ODE is measured on a scale of 0-5, with 1 being the least effected and 5 being   
   the most. Six out of seven subjects with ODE were grade 1, while the 7th   
   subject had a grade 3 eye. All seven subjects that developed clinical grade   
   ODE were men.   
       
   Results from the Ocular Health study will help doctors better understand   
   disorders such as glaucoma and Idiopathic Intracranial Hypertension (IIH) that   
   can plague people back on Earth. The latter is a condition in which   
   cerebrospinal fluid pressure rises and remains elevated for a long time,   
   causing severe headaches that even the strongest pain medications can't   
   touch.  Like glaucoma, the condition sometimes leads to vision loss and   
   blindness.   
       
   Says Otto,"This study will tell us more about noninvasive measurement of   
   intracranial pressure. The way doctors measure it now is through a spinal tap   
   or making a burr hole in the skull and inserting an intraventricular monitor."   
       
   "We are pushing the envelope in several areas of terrestrial clinical   
   medicine. NASA's Ocular Health study is providing new insights in neurology,   
   neurosurgery, ophthalmology, and cardio-vascular physiology. The clinical   
   community is very excited."   
       
   For more on studies on the International Space Station, go to ww   
   .nasa.gov/station   
       
       
   Regards,   
       
   Roger   
      
   --- DB 3.99 + Windows 10   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)