Of course this very much depends on a number of issues.
However, it is reasonable to expect this to be very much better about 4 to 6 months after surgery. If the redness is persisting at the end of such a time frame, I would have the ophthalmologist reassess what is going on. Also if you are using eye drops, these can also be irritating. If that is the case, call the ophthalmologist and discuss this with them.