Because their eyes are on the side of the head, they must tilt the head to see objects directly in front of them. They do not use their sense of smell-like other birds, robins have a terrible sense of smell. Experiments have ruled out the possibilities that robins feel vibrations that worms make or that robins hear worms moving. I did not find information to shed light on a comparison on hearing. However, in the reading I have done about eyesight, robins seem to have average eyesight.
All birds have a structure on the retina call the fovea that serves to magnify objects.
Because robins feed on worms which move very slightly, the robin needs a slightly larger fovea than say, a goldfinch which eats just seeds. A. See answer above. I honestly don't know. Thanks for helping us with these questions. A Robins do not eat seeds because their digestive system is not designed to work on seeds.