A closer look: Eyes on the mission
Tech. Sgt. Shawn Arehart, 730th Air Mobility Squadron communication navigation maintainer, describes symptoms to Capt. Benjamin Kolle, 374th Aerospace Medicine Squadron staff optometrist, at Yokota Air Base, Japan, Dec. 11, 2013. Symptoms such as headaches and blurred vision are usually a result of focusing difficulties. (U.S. Air Force photo by Airman 1st Class David Danford/Released)