Scientists have discovered a previously unknown layer lurking in the human eye. The newfound body part, dubbed Dua's layer, is a skinny but tough structure measuring just 15 microns thick, where one micron is one-millionth of a meter and more than 25,000 microns equal an inch. It sits at the back of the cornea, the sensitive, transparent tissue at the very front of the human eye that helps to focus incoming light, researchers say.

Shortly after the Haitian earthquake struck on January 12, 2010, my phone rang. I left the cold of Chicago seven days later. As an ophthalmologist, a medical doctor who specializes in eye care, I worked to provide immediate treatment for those injured.