So here's a way to notice this problem more obviously: go craft 1000 rounds of 10mm ammo as fast as you can with no regard to the strain on your optic muscles. Then stop and immediately focus your eyes on those same three places but go backwards! I mean go counter-clockwise for a minute from DONE to FIX to ITEM and back to DONE over and over. If you notice that makes your eyes feel "weird", well...that's how it feels when you agree with me lol.