Thanks to a new study out of the University of Houston, doctors now have a better understanding of the structural damage space travel has on a person's eyes. Using the latest in optical coherence tomography imaging, eye doctors have been able to locate the areas of the eyes affected by space flight-associated neuro-ocular syndrome (SANS).
In this new study, doctors examined eye scans of 15 astronauts before and after they went on a trip to the International Space Station. All of the astronauts chosen in this study experienced significant changes in their eye structure but no changes in their visual acuity. For a control, doctors compared the astronauts' eye scans with those taken from healthy patients.
Researchers used advanced algorithms when studying the astronauts' eye scans to pinpoint major areas of structural change. According to their research, astronauts suffering from SANS all have changes in three areas of their eyes.
The first major change researchers noticed in post-flight scans was that the retinae were thicker near the head rim margin of the optic nerve. Second, researchers said the Bruch's membrane between the retina and sclera had a different position in post-flight scans. Lastly, scientists discovered SANS patients had more choroidal folds than average.
The last of these findings was most shocking to scientists because it's not often associated with a rise in intracranial pressure. The only way scientists have been able to explain the increase in choroidal folds is that cranial fluids must move to different areas.
As of today, doctors don't have enough data to confirm whether these changes in the structure of the eyes have any long-term negative effects on astronauts' vision. Senior researchers hope the findings from this study will help researchers better understand SANS.
Nimesh Patel, who teaches optometry at the University of Houston, was the lead researcher on this project. In addition to working on this SANS study, Dr. Patel is also involved in NASA's Ocular Health ISS Study, which is concerned with examining the changes in astronauts' eye structure during space travel.
Anyone can check out this study in full in a recent edition of JAMA Ophthalmology. The title of this paper is, "Optical Coherence Tomography Analysis of the Optic Nerve Head and Surrounding Structures in Long-Duration International Space Station Astronauts."