In hockey, there are certain "injury plays" that are more common than others. Elbows to the head, pucks to the face and skates to the leg all happen more frequently than what Brandon Prust just suffered.
Prust just took a thumb to the eye.
The Canadiens forward was chasing a puck along the boards when Rangers defenseman Ryan McDonagh squeezed him into an awkward position. No video, but as you can see from this screencap it looks like McDonagh's thumb caught Prust right in the eye.
Prust immediately reached for his face in pain and went to the bench for repairs. He started pointing at his eye and seemed to indicate that his contact had slipped up to the top of his eyeball. Or something. I'm not quite sure how contacts work.
The way he was staring wide-eyed pretty much confirmed it. I personally don't wear contacts but I can imagine that's quite an uncomfortable feeling. Prust rejoined the team on the bench just a few minutes later.