We know most about how this problem impacts eyeballs, though it’s possible eyes are just the most detectable form of damage, and more subtle effects are happening to the brain itself. We aren’t going to linger on this because at the moment the data are unclear, but there is a possibility that space conditions have cognitive effects. Frankly, between the radiation and the fluid shifts, cumulative brain damage doesn’t sound like an especially wild conjecture. If this is a subtle issue that gets worse over time, it’ll take on a lot of importance for any space-settlement plan.
