vision

Trent Barton, a volunteer for the study looking at pressure inside the brain during space flights. Courtesy of David Ham hide caption

A simulation from the Neitz lab of what colorblindness looks like, with normal color vision on the left and red-green colorblindness on the right. Courtesy of Neitz Laboratory hide caption

In sighted people, the part of the brain that recognizes faces is linked to the brain's visual system. But in blind people it seems wired to circuits that process sound. Tina Zellmer/Ikon Images/Corbis hide caption

Surprise! Not one of these things contains a single speck of blue pigment. Evan Leeson/Bob Peterson/lowjumpingfrog/Look Into My Eyes/Flickr hide caption

This is a re-creation of a color plate from Interaction of Color, by Josef Albers. The two X's are are exactly the same — it's the different backgrounds that make them look like very different colors. Source: Josef Albers Interaction of Color hide caption

One of the scariest parts of advanced macular degeneration can be losing the ability to read facial expressions. Maria Pavlova/iStockphoto hide caption

A view of Interstate 65 in Alabama through bioptic lenses, which allow people who are severely nearsighted to drive. Dan Carsen/WBHM hide caption