Master Sgt. Mark Slater, 28th Medical Operations Squadron NCO in charge of optometry, administers a corneal topography test to Airman 1st Class Jordan Fishburn, 28th Logistics Readiness Squadron aircraft parts store technician, during a pre-operation procedure in the optometry clinic at Ellsworth Air Force Base, S.D., Oct. 24, 2014. The test maps a patient’s cornea for raised areas and surface inconsistencies to prevent infections or degenerative diseases. (U.S. Air Force photo by Senior Airman Zachary Hada/Released)