Surprising body changes in zero-G space environment

In space, the absence of gravity causes various changes in the human body. Astronauts can grow taller as their spines elongate, but this can lead to back pain. The heart becomes smaller and changes shape due to easier blood circulation. Bones lose calcium and become brittle, necessitating exercise to maintain bone density. Vision can be affected by changes in cranial pressure, requiring different prescriptions of glasses. Despite these challenges, the spirit of exploration makes these changes worthwhile.

Describe the impact of microgravity on bones and how astronauts counteract this effect.

What vision changes might astronauts experience in space and what measures are taken?