Notice not only is his eye cut in several places, the huge below, the huge one above, the one on the eye lid, his lip is busted and blackend and blue, his other eye seems quiet red, perhaps on the verge of cutting. also notice the cut on his forehead going horizontal and one above his eye going straight.
He fought bravely but needed to be protected from his own bravery, had he been allowed to continue the fight he'd probably just end up with a detatched retina and end up going blind and still losing the fight if not being knocked out. Besides, that cut would have opened up more and more, and every punch would be a punch to the eye, and eventually his skin would be falling off in chunks around the ring and more blood would pour out. People thinking Klitschko could have won this fight are in fantasy land. Lewis has never gone down after round 5. Klit was stopped in round 6. If there was a round 7, it'd just be stopped them because lewis would keep punching that eye.