This is what masking is for. In your example you would mask everything except for the eye (it might be faster to mask just the eye and then invert the mask). http://docs.pixologic.com/user-guide/3d-modeling/modeling-basics/masking/
Hey Guys, I have a question. I created a head in Zbrush and now I want to move for example the Eye...But when I do that, everything around the eyes moves too...I dont want that. How can I make sure to move only certain parts of my face? Thanks.