From the Sefer Nishmas Avraham Siman 182
וכן שמעתי מהגרש״ז אויערבאך זצ״ל לגבי בחור שצמחו לו שערות בין שתי גבות עיניו שזה נקרא מום ומותר לו להסירם: Uni brow is called a blemish and it can be removed.
The Shulchan Aruch 182:1 itself holds like the Rambam that one can remove other hair from the body with scissors except for the armpits and bais ha'erva. However there is a Mordichai that holds it is assur unless it causes the person tzar(pain),but the Shulchan Aruch doesn't bring that opinion down.
See here Nazir 58b for the discussion of this topic.