“Not all babies’ eyes change color,” Chasnovitz said. “But if babies are born with light eyes, then sometimes their eyes will slowly darken over the first year.”How do babies’ eyes change color? In other words, if both of a baby’s parents have brown eyes, that doesn’t mean their offspring will also have brown eyes. “Two people with lighter eyes are more likely to have a baby with lighter eyes. But if a grandparent has light eyes, they might end up with light eyes,” Chasnovitz said.