Petty Officer 3rd class Ryan Pritchard looks through the center of a Fresnel lens. Petty Officer 3rd class Ryan Pritchard looks through the center of a Fresnel lens while testing a new lamp to ensure it is working properly in the lighthouse at Naval Air Station Pensacola, Fla., on Aug. 13, 2004. SHARE: Download: Full Size (0.09 MB) Credit: VIRIN: 961225-W-CSC08-309.jpg Photo Gallery