U.S. Air Force Dr. (Maj.) Scott Barnes, 633rd Surgical Operations Squadron ophthalmic surgeon, performs a cataract extraction surgery at U.S. Air Force Hospital Langley at Langley Air Force Base, Va., Dec. 17, 2013. The 633rd SGCS and the other five 633rd Medical Group squadrons provide medical care for more than 40,000 service members, dependents and retirees. (U.S. Air Force photo by Airman 1st Class R. Alex Durbin/Released)