For Manny, LASIK was a ""no-brainer"". He used to be a .600 hitter on his baseball team. When his vision started to become a little blurry it was not possible for him to wear eyeglasses comfortably, and he didn't like the idea of contact lenses. So, he walked around (and played ball) seeing just a little blurry. This can obviously affect how soon one picks up the rotation of the stitching on the seams of a baseball, and therefore affects timing of the swing, detection of type of pitch (curveball, change-up, slider, fastball).
Manny should be a much better hitter with his vision corrected compared to not corrected. If LASIK is the best option for him, so be it!
Good luck in the playoffs!
PS: While Manny does play baseball at a serious amateur level, he does not play for a Dodger farm team. He wore his Eric Gagne Dodger jersey because he's also a big fan of the marquis Dodger player.