Making a traditional glass lens requires a lot of experience, skill, and patience grinding a piece of glass to the required shape, and is not for the casual experimenter. Making a glass Fresnel ...

Eyeglasses spread throughout the world and ... While not useful for cameras, the fresnel lens came around this time in 1818 and saved hundreds if not thousands of ships. The French Commission ...

Closeups of Secretary of State Clinton taken during her Senate testimony Wednesday revealed that her head injury last month left her with lingering vision problems. As she testified about the ...