Try some really slow food - like cut pieces of worms as Amy suggested. Also you could try getting small crickets and removing a leg so they can't hop away. (both sound terrible, but hey the frog's gotta eat)
Whatever you can find that is the size of the space between his eyes to feed him.

I had a toad with very VERY poor eyesight, and I had to put him in a small bowl with food so that the food was in a small enough space that he could find and catch it.