Bifocals
[2] On the contrary, the College of Optometrists concluded: John Isaac Hawkins, the inventor of trifocal lenses, coined the term bifocals in 1824 and credited Benjamin Franklin.[citation needed] In 1955, Irving Rips of Younger Optics created the first seamless or "invisible" bifocal, a precursor to progressive lenses.[10] The advantages were wide reading area, less prismatic effects and no image jump between distance and close viewing.Computer monitors are generally placed directly in front of users and can lead to muscle fatigue due to the unusual straight and constant movement of the head.[citation needed] The aquatic larval stage of the diving beetle Thermonectus marmoratus has, in its principal eyes, two retinas and two distinct focal planes that are substantially separated (in the manner of bifocals) to switch their vision from up-close to distance, for easy and efficient capture of their prey, mostly mosquito larvae.
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