. | . |
Probable cause and potential prevention of vision deterioration in space found by Staff Writers Dallas TX (SPX) Jan 18, 2017
Vision deterioration in astronauts who spend a long time in space is likely due to the lack of a day-night cycle in intracranial pressure. But using a vacuum device to lower pressure for part of each day might prevent the problem, UT Southwestern Medical Center researchers said. Their study appears in the Journal of Physiology. A change in vision is the No. 1 health risk for astronauts who spend extended periods of time on the International Space Station. The new research showed that intracranial pressure in zero-gravity conditions, such as exists in space, is higher than when people are standing or sitting on Earth, but lower than when people are sleeping on Earth. The researcher's finding suggests that the constancy of pressure on the back of the eye causes the vision problems astronauts experience over time. To study how zero-gravity conditions affect intracranial pressure, UT Southwestern researchers recruited volunteer patients who had had a port (called an Ommaya reservoir) permanently placed in their head as part of treatment for cancer. The ports provided a way for researchers to measure intracranial pressure. NASA flights then flew the eight volunteers one by one on steep up-and-down maneuvers (parabolic flights) that created 20-second intervals of weightlessness. The researchers measured intracranial pressure during the zero-gravity intervals and compared these with intracranial pressure during standard times of sitting, lying face upward (supine), and lying with head inclined downward. "These challenging experiments were among the most ambitious human studies ever attempted as part of the Flight Operations parabolic flight program, and changed the way we think about the effect of gravity - and its absence - on pressure inside the brain," said senior author Dr. Benjamin Levine, Professor of Internal Medicine at UT Southwestern Medical Center and Director of the Institute for Exercise and Environmental Medicine (IEEM), jointly run by UT Southwestern and Texas Health Resources. "The information from these studies is already leading to novel partnerships with companies to develop tools to simulate the upright posture in space while astronauts sleep, thereby normalizing the circadian variability in intracranial pressure, and hopefully eliminating the remodeling behind the eye," said Dr. Levine, who holds the Distinguished Professorship in Exercise Sciences. The researchers have continued studying whether it is possible to lower intracranial pressure by means of a vacuum device that pulls blood away from the head. They previously showed that a negative pressure box that snuggly fits the lower body can lower intracranial pressure when applied for 20-minute periods. They will soon be testing the effect of the lower body negative pressure device on eye remodeling when negative pressure is applied for eight-hour periods. "Astronauts are basically supine the entire time they are in space. The idea is that the astronauts would wear negative pressure clothing or a negative pressure device while they sleep, creating lower intracranial pressure for part of each 24 hours," said first author Dr. Justin Lawley, Instructor in Internal Medicine at UT Southwestern and a researcher at the IEEM. The negative pressure device research was also used with patients with Ommaya ports. "We are extremely grateful to these brave men and women from around the country who volunteered to let us make these critical measurements on them during parabolic flight. They have been through a lot of medical procedures in their lives, and were nonetheless extremely altruistic, desiring to give something back to medical science," Dr. Levine said of the cancer patient volunteers.
Related Links UT Southwestern Medical Center Space Medicine Technology and Systems
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |