Ashwin et al. have come up with a fascinating observation during their testing of 15 men with autism-spectrum disorders using the Freiburg Visual Acuity and Contrast Test. They found them to have, on average, 20:7 vision. This means they can see the same detail on an object 20 meters away that a person with average vision can see at 7 meters. Birds of prey have roughly 20:6 vision. What gives these people with autism hawk-like vision isn't known.