Seeing Details...or Not

People only see details with a tiny area of the eye—a part of the retina called the fovea. This exhibit demonstrates the sensitivity of the fovea. After directly looking at a bright flash of light visitors find that for a moment or two they are unable to make out details in the street map in the exhibit. When a person looks directly at something, its image is focused on the fovea, which is packed with cone cells and allows the eye to see detail. After the flash, it takes these cells a few moments to recover their sensitivity.