Fireman Ethan Rooney undergoes a routine eye exam from Certified Ophthalmic Technician Johnny Knight Sr. Jan. 17 at Naval Health Clinic Charleston. The device used is a Phoropter, which measures the refractive error to determine an individual's spectacle prescription. Rooney is a student at the Naval Nuclear Power Training Command at Joint Base Charleston- Weapons Station. (U.S. Air Force photo/Airman First Class Ashlee Galloway)