Not the monitor.
You should notice that after a few days usage, all will return to its normal shape, however whenever you take your glasses off for a while after using the PC, you may find your eyes feel very fatigued.
This should only happen for a while, until your eyes get used to being worked harder by the glasses.
Dunno what's up with my eyes, but when I wear my glasses, the screen turns into a slight parallelogram (can't be bothered checking spelling). All's fine after a few hours though :)