Earthly Solution Improves Astronaut Vision


LOS ANGELES, Calif. (Ivanhoe Newswire) — NASA says up to two thirds of astronauts who spend extended amounts of time in space experience poor vision back on Earth. The culprit may be pressure changes in the brain, possibly caused by zero gravity. As trips to Mars come closer to reality, NASA and the Pacific Neuroscience Institute are teaming up to solve that problem. Researchers are turning to a relatively simple solution that begins here on Earth.

A year ago, Karen Lemen got hydrocephalus. Doctors put in a shunt to drain fluid from her brain. That shunt made her a good candidate for a study to help astronauts, because it gives doctors easy access to measure changes in blood pressure.

Lemen explained to Ivanhoe, “I was looking for a way to give myself, and the easiest way is to just give back and participate, and be a guinea pig if you will!”

Doctor Santosh Kesari is part of a NASA-funded study to develop a device that regulates pressure in astronauts’ eyes and brain in space. This thigh cuff may be the answer. In the test, participants move, wearing the cuff, which is tightened and loosened, changing blood pressure.

“What we’re doing is measuring the pressure in real time, by hooking the shunt up to an external pressure monitor and at the same time we’re having her sit up, lie flat, or head down and then checking the pressures,” Santosh Kesari, MD, PhD, of the John Wayne Cancer Institute stated. (Read Full Interview)

Early results show pressure in the brain can be adjusted by managing blood flow in the leg. Doctor Kesari is encouraged, but says there’s much work to do.

Doctor Kesari continued, “Can we use a thigh cuff at a certain pressure, certain times of the day, hours of the day, to prevent the long term consequences of that pressure change in space?”

Karen is thrilled she may help solve the puzzle for our astronauts.

There was a surprise benefit for one of the study participants: the thigh cuff relieved her chronic headaches. Doctor Kesari is working on a cuff or compression stockings to improve symptoms from pressure in the brain.

Contributors to this news report include: Wendy Chioji, Field Producer; Rusty Reed, Videographer; Cyndy McGrath, Supervising Producer; Gabriella Battistiol, Assistant Producer; Roque Correa, Editor.

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REPORT:          MB #4306

BACKGROUND: Scientists have long known spaceflight is bad for astronaut muscles and bones, but now new evidence suggests it may cause vision problems too. Optic abnormalities may occur similar to the ones that occur in patients with intracranial hypertension, a condition where pressure builds inside of the skull. MRI findings revealed that short and long term exposure to microgravity caused these abnormalities of the eyes, causing vision problems for astronauts. These problems were varied and numerous, from expansion of the cerebrospinal fluid space surrounding the optic nerve, to flattening of the back of the eyeball.

RESEARCH: Complete eye examinations before and after long-duration space flights were completed for participating crew members; such as refractive tests to determine errors, photos to capture detailed images of the retina along with associated blood vessels and nerves. Imaging technology captured high resolution retinal structures where the layers and thickness could be measured. Also, researchers took images of the eye and optic nerve, and measured pressure of cerebrospinal fluid surrounding the spinal cord. Finally a standard visual acuity test was given to document the ability to focus on images and objects at a certain distance.


NEW STUDY: A new NASA-funded study using a patient who had a shunt put in place to drain fluid from her brain gave doctors easy access to measure changes in her blood pressure. This could help their research in determining why astronauts experience poor vision when returning from space, as the culprit may be pressure changes in the brain possibly caused by zero gravity. Researchers are working to develop a thigh cuff device that regulates pressure in astronauts’ eyes and brains. Early results show pressure in the brain can be adjusted by affecting blood flow in the leg, but there is more work to be done. The thigh cuff did have a side effect of relieving one patient’s chronic headaches.

(Source: Santosh Kesari, MD, PhD)


Trace Longo

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Doctor Q and A

Read the entire Doctor Q&A for Santosh Kesari, MD, PhD, FANA, FAAN

Read the entire Q&A