Maj. Bryan Kemper (right), 28th Medical Operations Squadron chief of optometry, uses a bio-microscope to examine Airman 1st Class Nichole Porrini, 28th Security Forces Squadron flight member, during a health evaluation on Ellsworth Air Force Base, S.D., Dec. 13, 2011. 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 Zachary Hada/Released)