Eye for an eye basically means treat other how would you like to be treated.
so for instance, if i cut your eye out, would you want to cut my eye to make things even?
Or if a three year old accidently kills two year old, do you then kill the three year old?
Or if a man rapes a woman, raping him back may not be an equall punishment..
So personally, i don't agree with an eye for an eye.

if we all practiced 'an eye for an eye' soon we'd all be blind.