Maj. Charles Malone, 28th Medical Operations Squadron optometrist, performs a slit lamp test on Master Sgt. Mark Slater, 28th MDOS NCO in charge of optometry, at Ellsworth Air Force Base, S.D., Oct. 24, 2014. The test consists of visually evaluating the surface of the eye for anything harmful such as infections or disease. (U.S. Air Force photo by Senior Airman Zachary Hada/Released)