Although, if you compare his injured eye to his other eye, it does remain bloodshot for the entire film, so there's a definite possibility that it got hurt.
I think both of his eyes were always naturally bloodshot, just to make him look scarier

(Same principle as the Great Owl from
The Secret of NIMH having no pupils).
It was actually years before I became aware that Sharptooth had one bad eye. :blink: I noticed that one of his eyes was closed a lot, but since there aren't many shots where you can see that one eye is open and the other is shut, I just thought he closed or squinted his eyes a lot (Another example of my incredible capacity for stupidity

). Even when I did find out, I think I read in a synopsis that his eye was wounded, rather than noticing it myself.
Personally I think the inconsistency of Sharptooth's eye injury (it's not even the same eye all the time; there are a few scenes in which his left eye is shut and his right is open) is simply due to poor continuity, as a result of the scenes being animated in a different order than that in which they appear in the film (and the occasional need to flip the animated image). I think he was intended to originally have two good eyes (as evidenced by the scene in which Littlefoot is caught in the vines, immediately before Sharptooth is blinded; both of Sharptooth's eyes are clearly open), one of which gets put out by the thorns, leaving him with one bad eye for the rest of the film. Apparently the animators in charge of the scenes that took place before Sharptooth's injury were just not aware of this.
I think it’s plausible that Sharptooth’s injury motivated his pursuit of the gang, at least in part. The way I see it, all three suggested reasonsóhunger, revenge, and coincidenceómay have been the case. He was following his food source (the migrating dinosaur herds), so he was heading in the same direction as the gang; when he did come across them (perhaps he was even tracking them beforehand), he obviously saw it as an opportunity to fill his stomach; and if he recognized Littlefoot and/or Cera as the hatchling(s) who cost him his eye, it might have fueled his desire to kill them.
@pokeplayer984: That's still a pretty tame-looking wound, and was that dinosaur actually shown receiving it? I imagine the event of the injury itself would be quite messy in real life.
