Editing Contact lens (section)

==History==

===Origins and first functional prototypes===
[[File:Da Vinci's method of corneal neutralization.jpg|thumb|left|alt=Illustration of a large lens covering a man's face|Artist's impression of [[Leonardo da Vinci|Leonardo's]] method for neutralizing the refractive power of the cornea]]

[[Leonardo da Vinci]] is frequently credited with introducing the idea of contact lenses in his 1508 ''Codex of the eye, Manual D'',<ref name="Heitz" /> wherein he described a method of directly altering [[cornea]]l power by either submerging the head in a bowl of water or wearing a water-filled glass hemisphere over the eye. Neither idea was practically implementable in da Vinci's time.<ref name="Schifrin" />{{rp|9}} He did not suggest his idea be used for correcting vision; he was more interested in exploring mechanisms of [[accommodation (eye)|accommodation]].<ref name="Heitz">Heitz, RF and Enoch, J. M. (1987) "Leonardo da Vinci: An assessment on his discourses on image formation in the eye." ''Advances in Diagnostic Visual Optics'' 19—26, Springer-Verlag.</ref>

[[René Descartes|Descartes]] proposed a device for correcting vision consisting of a liquid-filled glass tube capped with a [[lens]]. However, the idea was impracticable, since the device was to be placed in direct contact with the cornea and thus would have made [[blinking]] impossible.<ref name=":0">{{Cite journal |last=Moreddu |first=Rosalia |last2=Vigolo |first2=Daniele |last3=Yetisen |first3=Ali K. |date=August 2019 |title=Contact Lens Technology: From Fundamentals to Applications |url=http://pure-oai.bham.ac.uk/ws/files/68302144/Contact_Lens_Technology_From_Fundamentals_to_Applications_1_.pdf |journal=Advanced Healthcare Materials |volume=8 |issue=15 |pages=1900368 |doi=10.1002/adhm.201900368 |pmid=31183972 |s2cid=184488183}}</ref>

In 1801, [[Thomas Young (scientist)|Thomas Young]] fashioned a pair of basic contact lenses based on Descartes' model. He used wax to affix water-filled lenses to his eyes, neutralizing their [[refractive power]], which he corrected with another pair of lenses.<ref name="Schifrin">{{Cite book |last=Leonard G. Schifrin |title=The Contact Lens Industry: Structure, Competition, and Public Policy |last2=William J. Rich |date=December 1984 |publisher=United States [[Office of Technology Assessment]]}}</ref><ref name=":0" />

[[John Herschel]], in a footnote to the 1845 edition of the ''[[Encyclopedia Metropolitana]]'', posed two ideas for the visual correction: the first "a spherical capsule of glass filled with [[gelatin|animal jelly]]",<ref name="SinhaDada2017">{{Cite book |last=Rajesh Sinha |url=https://books.google.com/books?id=Ax8LDgAAQBAJ&pg=PA2 |title=Textbook of Contact Lenses |last2=Vijay Kumar Dada |date=31 January 2017 |publisher=JP Medical Ltd |isbn=978-93-86150-44-8 |pages=2–}}</ref> the second "a mould of the cornea" that could be impressed on "some sort of transparent medium".<ref>[http://www.eyetopics.com/articles/18/1/The-History-of-Contact-Lenses "The History of Contact Lenses."] {{Webarchive|url=https://web.archive.org/web/20081011022433/http://www.eyetopics.com/articles/18/1/The-History-of-Contact-Lenses |date=11 October 2008 }} eyeTopics.com. Accessed 18 October 2006.</ref> Though Herschel reportedly never tested these ideas, they were later advanced by independent inventors, including Hungarian physician Joseph Dallos, who perfected a method of making molds from living eyes.<ref name="mastereyeassoc">{{Cite web |title=History of Contact Lenses and Improved Technology |url=https://www.mastereyeassociates.com/contact-lens-history |access-date=14 September 2019 |website=Master Eye Associates |ref=mastereyeassoc}}</ref> This enabled the manufacture of lenses that, for the first time, conformed to the actual shape of the eye.<ref>{{Cite book |title=Van Nostrand's Scientific Encyclopedia |year=2005 |isbn=0471743984 |chapter=Contact Lenses |doi=10.1002/0471743984.vse2040}}</ref>

[[File:Adolf Fick-adjust.png|thumb|upright|In 1888, [[Adolf Gaston Eugen Fick]] was the first to successfully fit contact lenses, which were made from blown glass]]

Although [[Louis J. Girard]] invented a [[scleral contact lens]] in 1887,<ref name="Timetables">{{The Timetables of Science|pages=367}}</ref> it was German ophthalmologist [[Adolf Gaston Eugen Fick]] who in 1888 fabricated the first successful [[Afocal system|afocal]] scleral contact lens.<ref>{{Cite web |title=Adolf Eugen Fick (1852–1937) |url=http://www.sciencemuseum.org.uk/broughttolife/people/adolfeugenfick.aspx |url-status=dead |archive-url=https://web.archive.org/web/20150517070106/http://www.sciencemuseum.org.uk/broughttolife/people/adolfeugenfick.aspx |archive-date=17 May 2015 |access-date=26 March 2015}}</ref> Approximately {{convert|18–21|mm|abbr=on}} in diameter, the heavy [[Glassblowing|blown-glass]] shells rested on the less sensitive rim of tissue surrounding the cornea and floated on a [[dextrose]] solution. He experimented with fitting the lenses initially on rabbits, then on himself, and lastly on a small group of volunteers, publishing his work, ''"Contactbrille"'', in the March 1888 edition of ''Archiv für Augenheilkunde''.<ref>{{Cite journal |last=Heitz |first=R |date=September 2014 |title=The invention of the contact lenses (1888) |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1755-3768.2014.3773.x |journal=Acta Ophthalmologica |language=en |volume=92 |issue=s253 |pages=0 |doi=10.1111/j.1755-3768.2014.3773.x |issn=1755-375X}}</ref> Large and unwieldy, Fick's lens could be worn only for a couple of hours at a time.<ref>{{Cite book |last=Sinha |first=Rajesh |url=https://www.worldcat.org/title/962009998 |title=Textbook of contact lenses |last2=Dada |first2=Vijay Kumar |date=2017 |publisher=Jaypee Brothers Medical Publishers (P) Ltd |isbn=978-93-86150-44-8 |edition=Fifth |location=New Delhi ; Philadelphia |oclc=962009998}}</ref> [[August Müller (inventor)|August Müller]] of [[Kiel]], Germany, corrected his own severe [[myopia]] with a more convenient blown-glass scleral contact lens of his own manufacture in 1888.<ref>{{Cite journal |last=Pearson |first=Richard M. |last2=Efron |first2=Nathan |date=September 1989 |title=Hundredth anniversary of August Müller's inaugural dissertation on contact lenses |journal=Survey of Ophthalmology |volume=34 |issue=2 |pages=133–141 |doi=10.1016/0039-6257(89)90041-6 |pmid=2686057}}</ref>

The development of [[polymethyl methacrylate]] (PMMA) in the 1930s paved the way for the manufacture of plastic scleral lenses. In 1936, optometrist [[William Feinbloom]] introduced a hybrid lens composed of glass and plastic,<ref>Robert B. Mandell. ''Contact Lens Practice'', 4th Edition. Charles C. Thomas, Springfield, IL, 1988</ref> and in 1937 it was reported that some 3,000 Americans were already wearing contact lenses.<ref>"Contact Lens for Eyes Now Common; It is Used as Substitute for Spectacles." Nashua (IA) Reporter, 28 April 1937.</ref> In 1939, Hungarian ophthalmologist Dr.István Györffy produced the first fully plastic contact lens.<ref>{{Cite journal |last=Gyorgy |first=Salacz |date=January 2001 |title=Dr István Györffy, 1912–1999 |journal=Contact Lens and Anterior Eye |volume=24 |issue=4 |pages=180–182 |doi=10.1016/S1367-0484(01)80040-0}}</ref> The following year, German optometrist [[Heinrich Wöhlk]] produced his own version of plastic lenses based on experiments performed during the 1930s.<ref>Contact Lens History: How Contact Lenses Have Developed Through the Years. EyeHealth Central. Retrieved from https://www.contactlenses.co.uk/education/history.htm</ref>

===Corneal and rigid lenses (1949–1960s)===

In 1949, the first "corneal" lenses were developed.<ref>U.S. Patent No. [https://patents.google.com/patent/US2510438 2,510,438], filed 28 February 1948.</ref><ref>"The Corneal Lens", ''The Optician'', 2 September 1949, pp. 141–144.</ref><ref>"Corneal Contact Lenses", ''The Optician'', 9 September 1949, p. 185.</ref><ref>"New Contact Lens Fits Pupil Only", ''[[The New York Times]]'', 11 February 1952, p. 27.</ref> These were much smaller than the original scleral lenses, as they sat only on the cornea rather than across all of the visible ocular surface and could be worn up to 16 hours a day. PMMA corneal lenses became the first contact lenses to have mass appeal through the 1960s, as lens designs became more sophisticated with improving manufacturing technology.<ref>{{Citation |last=Pal |first=Subrata |title=The Eye and Its Artificial Replacement |date=2014 |work=Design of Artificial Human Joints & Organs |pages=219–249 |url=http://link.springer.com/10.1007/978-1-4614-6255-2_14 |access-date=2024-08-29 |place=Boston, MA |publisher=Springer US |language=en |doi=10.1007/978-1-4614-6255-2_14 |isbn=978-1-4614-6254-5}}</ref>  On October 18, 1964, in a television studio in Washington, D.C., [[Lyndon Baines Johnson]] became the first President in the history of the United States to appear in public wearing contact lenses, under the supervision of Dr. Alan Isen, who developed the first commercially viable soft-contact lenses in the United States.<ref>{{Cite book |last=Rosenthal |first=J. William |title=Spectacles and Other Vision Aids: A History and Guide to Collecting |date=1996 |publisher=Norman Publishing |isbn=978-0930405717 |page=379}}</ref><ref>{{Cite news |last=Smith |first=William D. |date=18 April 1971 |title=Soft-Lens Clamor |url=https://www.nytimes.com/1971/04/18/archives/softlens-clamor-tiny-piece-of-plastic-attracts-wall-street-interest.html |access-date=29 November 2018 |work=The New York Times}}</ref><ref>{{Cite news |date=December 6, 1964 |title=nytimes archive |url=https://www.nytimes.com/1964/12/06/archives/but-they-make-marriage-contracts-with-girls-who-wear-contacts.html |access-date=2018-08-24 |work=[[The New York Times]]}}</ref>

Early corneal lenses of the 1950s and 1960s were relatively expensive and fragile, resulting in the development of a market for contact lens insurance. Replacement Lens Insurance, Inc. (now known as [[RLI Corp.]]) phased out its original flagship product in 1994 after contact lenses became more affordable and easier to replace.{{Citation needed|date=June 2017}}

===Gas permeable and soft lenses (1959–present)===

One of the major disadvantages of PMMA lenses is that they allow no oxygen to get through to the [[conjunctiva]] and cornea, causing a number of adverse and potentially serious clinical effects. By the end of the 1970s and through the 1980s and 1990s, a range of [[Oxygen permeability|oxygen-permeable]] but rigid materials were developed to overcome this problem. Chemist [[Norman Gaylord]] played a prominent role in the development of these new oxygen-permeable contact lenses.<ref name="bc">{{Cite web |last=Pearce, Jeremy |date=23 September 2007 |title=Norman Gaylord, 84; helped develop type of contact lens |url=http://www.boston.com/news/globe/obituaries/articles/2007/09/23/norman_gaylord_84_helped_develop_type_of_contact_lens/ |access-date=6 October 2007 |website=(New York Times News Service) |publisher=[[The Boston Globe]]}}</ref> Collectively, these [[polymers]] are referred to as ''[[RGP lens|rigid gas permeable]]'' or RGP materials or lenses. Though all the above contact lens types—sclerals, PMMAs and RGPs—could be correctly referred to as "rigid" or "hard", the latter term is now used for the original PMMAs, which are still occasionally fitted and worn, whereas "rigid" is a generic term for all these lens types; thus, hard lenses (PMMAs) are a subset of rigid contact lenses. Occasionally, the term "gas permeable" is used to describe RGPs, which is somewhat misleading as soft contact lenses are also gas permeable in that they allow oxygen to get through to the ocular surface.

[[File:Prof. Ing. RTDr. Otto Wichterle.jpg|thumb|upright|[[Otto Wichterle]] (pictured) and [[Drahoslav Lím]] introduced modern soft hydrogel lenses in 1959.]]

The principal breakthrough in soft lenses was made by Czech chemists [[Otto Wichterle]] and [[Drahoslav Lím]], who published their work "Hydrophilic gels for biological use" in the journal ''Nature'' in 1959.<ref name="Wichterle">{{Cite journal |vauthors=Wichterle O, Lim D |year=1960 |title=Hydrophilic gels for biological use |journal=Nature |volume=185 |issue=4706 |pages=117–118 |bibcode=1960Natur.185..117W |doi=10.1038/185117a0 |s2cid=4211987}}</ref> In 1965, [[National Patent Development Corporation]] (NPDC) bought the American rights to produce the lenses and then sublicensed the rights to [[Bausch & Lomb]], which started to manufacture them in the United States.<ref>{{Cite web |title=CONTACT LENS HISTORY – Otto Wichterle |url=http://www.andrewgasson.co.uk/opioneers_wichterle.htm |url-status=dead |archive-url=https://web.archive.org/web/20150129033858/http://www.andrewgasson.co.uk/opioneers_wichterle.htm |archive-date=29 January 2015 |access-date=26 March 2015 |df=dmy-all}}</ref> The Czech scientists' work led to the launch of the first [[hydrogel]] contact lenses in some countries in the 1960s and the first approval of the Soflens material by the US [[Food and Drug Administration]] (FDA) in 1971. These soft lenses were soon prescribed more often than rigid ones, due to the immediate and much greater comfort (rigid lenses require a period of adaptation before full comfort is achieved). Polymers from which soft lenses are manufactured improved over the next 25 years, primarily in terms of increasing oxygen permeability, by varying the ingredients. In 1972, British optometrist Rishi Agarwal was the first to suggest disposable soft contact lenses.<ref>{{Cite journal |last=Agarwal Rishi K |year=1972 |title=Some Thoughts on Soft Lenses |journal=The Contact Lens |volume=4 |issue=1 |page=28}}</ref><ref>{{Cite journal |year=1988 |title=Editorial note |journal=American Journal of Optometry and Physiological Optics |volume=65 |issue=9 |page=744}}</ref>

In 1998, the first silicone hydrogel contact lenses were released by [[Ciba Vision]] in Mexico. These new materials encapsulated the benefits of silicone which has extremely high [[oxygen permeability]]—with the comfort and clinical performance of the conventional hydrogels that had been used for the previous 30 years. These contact lenses were initially advocated primarily for extended (overnight) wear, although more recently, daily (no overnight) wear silicone hydrogels have been launched.

In a slightly modified molecule, a polar group is added without changing the structure of the silicone hydrogel. This is referred to as the Tanaka monomer because it was invented and patented by {{ill|Kyoichi Tanaka|ja|田中恭一}} of {{ill|Menicon|ja|メニコン}} Co. of Japan in 1979. Second-generation silicone hydrogels, such as [[galyfilcon A]] ([[Acuvue]] Advance, Vistakon) and [[senofilcon A]] (Acuvue Oasys, Vistakon), use the Tanaka monomer. Vistakon improved the Tanaka monomer even further and added other molecules, which serve as an internal [[wetting agent]].<ref name="szcz" />

[[Comfilcon A]] (Biofinity, CooperVision) was the first third-generation polymer. Its patent claims that the material uses two siloxy macromers of diverse sizes that, when used in combination, produce very high oxygen permeability for a given water content. [[Enfilcon A]] (Avaira, CooperVision) is another third-generation material that is naturally wet; its water content is 46%.<ref name="szcz" />