Yes, cats whisker can be trimmed... However, the whiskers are a strong sensory device. Trimming them too much may result in your cat acting as if it has no balance, or to bump into things from time to time. Whiskers are simply a thick facial hair. It does grow back, but takes time.

 Yes, you can trim cat whiskers but you got to make sure you don't trim them to much because yea what fontlow said it does help their balance but that is mostly a cats tail instead of whiskers. But if you trim them to much a cat will not want to eat because it helps them smell and taste their food.