They all come back shorter and near sited among other problems.
Don’t know about the near-sightedness, but they come back taller, not shorter. The lower, or lack of, gravity causes the spinal column to decompress, making them taller, at least temporary.
Even Howard was taller when he came back.
I swear he said shorter. I could be wrong.
As far as the near sited, it has to do with the changes to the shape of the eye ball. My NASA friend state that Dartmouth was doing a study on the effects of low gravity on changes to the human eye ball and how to measure them. He is in charge of managing NASA grant money to colleges/universities doing research. Many of these experiments end up on the International Space station.
It is not that they get shorter it is bone loss. I assumed this meant they were getting shorter.
https://www.smithsonianmag.com/science-nature/what-happens-human-body-space-180958259/
“The fluids in your body will shift upwards to your head, which could put pressure on your eyes causing vision problems.”
This quote is from a NASA article regarding the effects of low gravity and extended exposure to radiation on the human body.