Yes, people, he is aiming without an eye. But be real; this is Deathstroke. He doesn't need eyes to fire a rifle. Or hands. He could probably kill you with the...well, I'm looking all over and can't find something that he would be incapable of using. Hell, he's the only guy who could plausibly, literally, look daggers at you and kill you with a stare.
Anyway; this skill-level is unreal. I had to spend two solid minutes working out if it was a painting or the cosplay of a millionaire.
When you know guns well enough, aiming down the sights isn't even needed, so as long as he has one eye on target (as he does), he doesn't need the other eye. "Point and shoot. It's just point and shoot." This is some incredible work, I agree. I love how in your art, you not only go for accuracy in the character which your are portraying, but everything else – especially the weapons – in the picture too! I've seen so many weapons-out-of-time (AK-47s in WWII, MP-40s in the hands of modern Secret Service...) that it is quite refreshing to see someone with the knowledge and patience behind what they do.
hahaha love it! Yes he is blind in that eye. But this image is after the killshot, so it doesn't really matter if he is or isn't. At least for our purposes but you're right he can't see a thing out of that side