Editing Glasses (section)

=== Later developments ===
The American scientist [[Benjamin Franklin]], who had both [[myopia]] and [[presbyopia]], invented [[bifocals]]. Historians have from time to time produced evidence to suggest that others may have preceded him in the invention; however, a correspondence between [[George Whatley]] and [[John Fenno]], editor of ''[[The Gazette of the United States]]'', suggested that Franklin had indeed invented bifocals, and perhaps 50 years earlier than had been originally thought.<ref>{{Citation |title=The 'Inventor' of Bifocals? |url=http://www.college-optometrists.org/en/knowledge-centre/museyeum/online_exhibitions/artgallery/bifocals.cfm |archive-url=https://web.archive.org/web/20110613044912/http://www.college-optometrists.org/en/knowledge-centre/museyeum/online_exhibitions/artgallery/bifocals.cfm |publisher=The College of Optometrists |archive-date=13 June 2011 |url-status=dead}}</ref> The first lenses for correcting [[astigmatism]] were designed by the British astronomer [[George Airy]] in 1825.<ref>{{Citation |last=Bruen |first=Robert |title=Sir George Biddell Airy |url=http://www.lucasianchair.org/19/airy.html |work=The Lucasian Chair of Mathematics at Cambridge University |publisher=Robert Bruen |access-date=1 January 2014 |archive-date=25 January 2021 |archive-url=https://web.archive.org/web/20210125092211/http://www.lucasianchair.org/19/airy.html |url-status=dead }}</ref>

Over time, the construction of frames for glasses also evolved. Early eyepieces were designed to be either held in place by hand or by exerting pressure on the nose (''[[pince-nez]]''). [[Girolamo Savonarola]] suggested that eyepieces could be held in place by a ribbon passed over the wearer's head, this in turn secured by the weight of a hat. The modern style of glasses, held by temples passing over the ears, was developed sometime before 1727, possibly by the British optician [[Edward Scarlett]]. These designs were not immediately successful, however, and various styles with attached handles such as "[[scissors-glasses]]" and [[lorgnette]]s were also fashionable from the second half of the 18th century and into the early 19th century.

In the early 20th century, [[Moritz von Rohr]] and [[Carl Zeiss AG|Zeiss]] (with the assistance of H. Boegehold and A. Sonnefeld<ref>{{Citation |title=Eyeglass Lenses and Visual Aids from Industrial Production |url=http://www.zeiss.com/C12567A100537AB9/Contents-Frame/6B49EEA709EAE719C1256919003DAE2B |publisher=Zeiss |access-date=2 September 2007}}</ref>) developed the Zeiss Punktal spherical point-focus lenses that dominated the eyeglass lens field for many years. In 2008, [[Joshua Silver]] designed eyewear with adjustable corrective glasses. They work by using a built-in syringe to pump a [[silicone]] solution into a flexible lens.<ref>{{Citation |last=Whiteman |first=Honor |title=Self-adjustable eyeglasses: how one man's vision is helping others to see better |date=12 November 2015 |url=https://www.medicalnewstoday.com/articles/302550 |work=Medical News Today |publisher=Red Ventures |access-date=25 October 2021}}</ref>

Despite the popularity of [[contact lenses]] and [[laser]] [[Refractive surgery|corrective eye surgery]], glasses remain very common, as their technology has improved. For instance, it is now possible to purchase frames made of special [[memory metal]] alloys that return to their correct shape after being bent. Other frames have spring-loaded hinges. Either of these designs offer dramatically better ability to withstand the stresses of daily wear and the occasional accident. Modern frames are also often made from strong, lightweight materials such as [[titanium]] alloys, which were not available in earlier times.

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File:Don francisco de quevedo-villegas.jpg|A portrait of [[Francisco de Quevedo y Villegas]], 1580–1645
File:Harry S. Truman.jpg|[[Harry S. Truman]], 33rd President of the United States, had poor vision.
</gallery>