Space Travel Truth

Research performed on the International Space Station shows prolonged time in space can cause temporary, and sometimes permanent, blindness, said Julie Robinson, the chief scientist of the International Space Station. “One of the things we discovered in the last 10 years is that some astronauts, when they go into space, actually have vision loss. A few of those astronauts have permanent vision loss that isn’t reversed when they turn to Earth.”

At first, scientists thought it was a minor issue, but not anymore.“We thought it was reversible,” Robinson said. “We just didn’t realize that it was a real problem until we started having enough experience on the space station, since it doesn’t happen in everybody.

“We had a few crew members coming home with such significant vision loss that people realized that it wasn’t normal,” Robinson said. “And then we started looking into those, doing extra imaging, some spinal taps on astronauts, and found out they had really high spinal pressures and we realized there was something going on here that really mattered.”

Dr. Steven Laurie, the lead scientist for Spaceflight Associated Neuro-ocular Syndrome research says, “We have known since astronauts flew short-duration Space Shuttle missions that vision changes during spaceflight. However, once we started seeing swelling at the back of the eye surrounding the optic nerve, this became more concerning because it has the potential to lead to long-term changes in vision that cannot be fixed with new prescription lenses.”

On July 12, 2012 NASA published a report on the effect of space travel on the vison of astronauts. It was titled “Risk of Spaceflight-Induced Intracranial Hypertension and Vision Alterations”. Here is an excerpt from the NASA document:

“Over the last 40 years there have been reports of visual acuity impairments associated with spaceflight through testing and anecdotal reports. Until recently, these changes were thought to be transient, but a comparison of pre and postflight ocular measures have identified a potential risk of permanent visual changes as a result of microgravity exposure.

It is thought that the ocular structural and optic nerve changes are caused by events precipitated by the cephalad-fluid shift crewmembers experience during long-duration spaceflight.

To date, fifteen long-duration crewmembers have experienced in-flight and postflight visual and anatomical changes including optic-disc edema, globe flattening, choroidal folds, and hyperopic shifts as well as documented postflight elevated intracranial pressure (ICP). In the postflight time period, some individuals have experienced transient changes while others have experienced changes that are persisting with varying degrees of severity and permanence.”

NASA has determined that the first documented case of a U.S. astronaut affected by the Spaceflight-Associated Neuro-Ocular Syndrome (SANS) occurred in an astronaut during a long-duration International Space Station (ISS) mission. The astronaut noticed a decrease in vision throughout the mission.

Additional cases of altered vision have been reported since, and one case was the report of a scotoma (visual field defect), which resulted in the astronaut having to tilt his head 15 degrees to view instruments and procedures. These visual symptoms persisted for over 12 months after flight.

This type of functional deficit is not only of concern to the individual, but is of concern to the mission and the ISS program managers.

Changes in vision are not uncommon in astronauts, especially among long-duration crewmembers. Specifically, 29% of short-duration and 60% of long-duration crewmembers reported degradation of eyesight.