In 2020, over 12,000 individuals applied to NASA’s astronaut program. This number just goes to show that many people want to become an astronaut, which isn’t surprising. After all, being in space is an experience like no other.
However, NASA has a rigid selection process. Out of those 12,000 applicants, only a handful will make it and become astronauts. Wondering exactly how selective NASA is? Well, since 1963, NASA has only accepted 350 individuals to train as astronaut candidates.
Do you have dreams of becoming an astronaut? Well, you’ll have to pass several tests, with one of the first being visual acuity. In this post, we’ll discuss several things about how vision relates to space travel, from NASA’s vision requirements right down to why so many NASA astronauts need to wear corrective lenses.
What are the vision requirements for NASA astronauts?
In NASA’s early days, astronauts had to pass extremely stringent vision requirements. NASA astronauts were required to have natural 20/20 vision. They were also not allowed to wear any type of corrective lenses. Lucky for today’s astronauts, NASA has relaxed its vision requirements.
However, loose vision requirements don’t make NASA applications less intense or rigorous. Modern NASA astronauts still have to pass many vision requirements, which can include (but are not limited to):
– NASA no longer requires astronauts to have naturally perfect vision. However, their vision must be correctable to 20/20 (for both eyes).
– NASA pilots cannot be colorblind
– In terms of colorblindness, NASA gives considerations to non-pilots and mission specialists.
Can astronauts wear contact lenses in space?
If NASA no longer requires astronauts to wear contact lenses in space, does that mean NASA astronauts can wear contact lenses or eyeglasses while they’re on missions in space? Yes, NASA now allows astronauts to wear contact lenses or prescription eyeglasses.
Many of today’s NASA astronauts are already wearing contact lenses or prescription eyeglasses. Reports indicate that around 80% of NASA’s current astronaut corps wear corrective lenses. As of June 2021, NASA has 45 active astronauts. If it is true that 80% of NASA’s astronaut corps wear corrective lenses, then it means that at least 36 astronauts in active duty at NASA wear either contact lenses or prescription eyeglasses.
If you are interested in becoming an astronaut but are worried that your vision issues will hinder your application, don’t worry. As long as your vision for both eyes is correctable to 20/20, then you have a chance of passing NASA’s vision requirements. Having perfect or near-perfect vision isn’t enough, though. Becoming a NASA astronaut also means passing a battery of demanding physical and psychological tests.
Why are so many astronauts wearing corrective lenses?
Being in space for months and months has a negative impact on the eyes and vision. Astronauts spend extended periods in space, which is why more than two-thirds of NASA’s astronaut corps wear either contact lenses or prescription eyeglasses.
The microgravity in space affects intraocular pressure, which is the fluid pressure in the eye. Intraocular pressure helps maintain the shape of the human eye, so keeping it normal is important. However, it’s easier for the human body to control intraocular pressure when on Earth than when in space.
On Earth, gravity pulls fluids towards one’s lower extremities. In space, though, the lack of gravity pushes fluids towards the head. This lack of gravity is what causes fluids in the eyes of astronauts to shift, which in turn results in changes to eye structure as well as a myriad of long-term—and, in many cases, permanent—vision problems.
How did NASA find out about vision problems in astronauts?
NASA studied many astronauts and determined that a significant number of them experienced long-term vision issues and changes to their eye structure. The space agency found that several astronauts had problems with both near and distance vision. NASA also found eye structure changes that included changes to the shape of the retina, optic nerve, and the back of the eyeball.
In a survey of 300 astronauts (both male and female), NASA found that 23% of astronauts who went on short-term flights and 49% of astronauts who went on long-term flights experienced near and distance vision problems. Some of these astronauts experienced these problems for years long after they returned from space.
Author’s bio: Jericho Gonzales is a Content Marketing Specialist at Lens.com. Writing is his passion, and he specializes in tech-based and consumer product-based writing. His other passions lie in the worlds of fantasy and science fiction. When he isn’t busy with wordcraft, he loves to immerse himself in those worlds through novels, video games, TV shows, or movies.