Yes and No. The question is a bit vague. Not all combat scenarios and opponents are the same. If he was in combat and had time to evade his opponent or find a way to immobilize them, then he could activate the eye and the cast a spell. Otherwise he's not getting the chance without some prep. Kaecilius almost stabbed him and he was like 60 meters away from Strange.
Not anymore now that he lost the time gem. With it, yeah, he did it againat Kaecillius and the other Zelots. Shame they happened to draw power from a being that is outside of time and could get out, but even the other Sorcerers like Wong and Mordo could not move anymore.
@DammeFavour: Maw prevented him from using the gem so how is he relevant.