Isabella Beukes, of Santa Rosa, Calif., has been legally blind for more than 40 years. An experimental treatment derived from embryonic stem cells seems to have enabled her now to see not just color but also some shapes. Tim Hussin for NPR hide caption

itoggle caption Tim Hussin for NPR

Vending machines at the University of Arkansas in Little Rock, Ark., were stocked with more healthful snacks in 2006. Danny Johnston/AP hide caption

itoggle caption Danny Johnston/AP

Age-related macular degeneration accounts for more than half of all cases of blindness in the United States. iStockphoto.com hide caption

itoggle caption iStockphoto.com

How much oxygen should severely premature infants receive? A study that sought to answer the question has been criticized for not fully informing parents about the risks to their children. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Sue Freeman, 78, checks her email at her home in Laguna Beach, Calif., on Saturday. She says her eyesight improved markedly since she received an experimental stem-cell procedure last July. Melissa Forsyth for NPR hide caption

itoggle caption Melissa Forsyth for NPR