Russian scientists are studying the brains of astronauts: looking for the cause of visual impairment

Excessive strength training has been cited as one possible cause.

Up to 48% of NASA astronauts on the ISS reported to doctors a temporary decrease in visual acuity after returning from orbit. The problem is not so acute for Russian cosmonauts, but experts are determined to study it in order to prevent its possible occurrence in the future.

Photo: Gennady Cherkasov

According to the American Academy of Ophthalmology, the cause of visual impairment after flight is associated with the so-called Spaceflight-Associated Neuro-Ocular Syndrome (SANS). This is a set of symptoms found in astronauts who performed long-term space flights.

Russian scientists decided to find a more accurate cause of neuro-ocular syndrome by examining post-flight MRI images of the astronauts' brains.

According to the head of the Laboratory for the Prevention of Hypogravity Disorders of the IBMP RAS, Doctor of Biological Sciences Elena Fomina, at first experts assumed that the cause of SANS was increased intracranial pressure in microgravity conditions. Later, a number of hypotheses about the mechanisms of occurrence of SANS were tested, from morphological to metabolic. Experimental tests were carried out in ground-based models and on board the ISS. Unfortunately, scientists do not yet have a definite answer. According to the modern version, it is customary to talk about the polycausality of this syndrome.

However, IBMP specialists have their own hypothesis. According to her, the cause of visual impairment during space flight can also be strength exercises with heavy weights.

— When a state of straining occurs, intra-abdominal and intrathoracic pressure increases, and, as a result, intracranial pressure increases, explains the doctor of biological sciences. Sci. “Currently, a sufficient number of post-flight MRI scans of the astronauts’ brains have been accumulated, and we plan to compare what changes occur in those who took on high and low weights. Some crew members emulate their ISS partners and significantly exceed our recommendations. We have shown sufficient effectiveness of performing strength exercises with a weight equal to the weight of your body on Earth or 120–130 percent of it. In addition, it is better to do strength exercises every other day, and not every day, as astronauts do.

In any case, scientists will give the final answer to the question of why vision may suffer in orbit after a thorough study of the data obtained.