Maj. Bryan Kemper, 28th Medical Operations Squadron optometrist, uses a slit-lamp to view the eyes of Master Sgt. Juan Lopez, 28th Aircraft Maintenance Squadron production superintendent, during an eye exam at Ellsworth Air Force Base, S.D., Sept. 12, 2013. Optometrists use bio-microscopes to determine the health of the front and back surfaces of a patient’s eye. (U.S. Air Force photo by Airman 1st Class Alystria Maurer/Released)