U.S. Air Force Capt. Lauren Matthews, 633rd Aerospace Medicine Squadron optometrist, uses a slit lamp to examine the eyes of Senior Airman Cole Bonack, 633rd AMDS Optometry technician, at Langley Air Force Base, Va., Jan. 16, 2015. The Langley Optometry Clinic uses slit lamps to determine a patient’s ocular health by examining areas including the eyelids, cornea and iris. (U.S. Air Force photo by Airman 1st Class Areca T. Wilson/Released)