99th Aerospace Medicine Optometry
U.S. Air Force Master Sgt. David Sims, 57th Aircraft Maintenance Squadron first sergeant, has his eyes checked by Capt. (Dr.) William Catt, 99th Aerospace Medicine chief of aerospace optometry, June 7, 2013, at Nellis Air Force Base, Nev. Catt uses a magnifier, which intensifies the light into the eye and aids the doctor as he looks for diseases in the eye. (U.S. Air Force photo by Senior Airman Daniel Hughes)