Editing Contact lens (section)

===Care===
[[File:Lens-cover.jpg|thumb|alt=An open lens care. The lens caps are engraved with the letters L and R to indicate left and right. The case body is shaped as a pair of glasses and contains two holes for the lenses.|Lens case to store contacts]]

Lens care varies depending on material and wear schedule. Daily disposables are discarded after a single use and thus require no cleaning. Other lenses need regular cleaning and disinfecting to prevent surface coating and infections.

There are many ways to clean and care for contact lenses, typically called care systems or lens solutions:

;Multipurpose solutions
:The main attraction of multipurpose solutions is that the same solution can clean, rinse, disinfect and store lenses. Some multipurpose solutions also contain ingredients that improve the surface wettability and comfort of silicone hydrogel lenses. Studies showed that multipurpose solutions are ineffective against ''[[Acanthamoeba]]e''.<ref name="Johnston2009">{{Cite journal |last=Johnston |first=Stephanie P. |last2=Sriram |first2=Rama |last3=Qvarnstrom |first3=Yvonne |last4=Roy |first4=Sharon |last5=Verani |first5=Jennifer |last6=Yoder |first6=Jonathan |last7=Lorick |first7=Suchita |last8=Roberts |first8=Jacquelin |last9=Beach |first9=Michael J. |last10=Visvesvara |first10=Govinda |date=July 2009 |title=Resistance of Acanthamoeba Cysts to Disinfection in Multiple Contact Lens Solutions |journal=Journal of Clinical Microbiology |volume=47 |issue=7 |pages=2040–2045 |doi=10.1128/JCM.00575-09 |pmc=2708465 |pmid=19403771}}</ref><ref name="Padzik2014">{{Cite journal |last=Padzik |first=Marcin |last2=Chomicz |first2=Lidia |last3=Szaflik |first3=Jacek P. |last4=Chruścikowska |first4=Agnieszka |last5=Perkowski |first5=Konrad |last6=Szaflik |first6=Jerzy |date=November 2014 |title=In vitro effects of selected contact lens care solutions on Acanthamoeba castellanii strains in Poland |journal=Experimental Parasitology |volume=145 |pages=S98–S101 |doi=10.1016/j.exppara.2014.06.014 |pmid=24967738}}</ref><ref name="de Aguiar2013">{{Cite journal |last=Aguiar |first=Ana |last2=Oliveira Silveira |first2=Caroline |last3=Todero Winck |first3=Mari |last4=Rott |first4=Marilise |date=1 January 2013 |title=Susceptibility of Acanthamoeba to multipurpose lens-cleaning solutions |journal=Acta Parasitologica |volume=58 |issue=3 |pages=304–308 |doi=10.2478/s11686-013-0143-9 |pmid=23990426 |doi-access=free |hdl-access=free |hdl=10183/179379}}</ref> There is preliminary research on creating a new multipurpose solution that kills amoeba.<ref>{{Cite journal |last=Fears |first=Alyssa C. |last2=Metzinger |first2=Rebecca C. |last3=Killeen |first3=Stephanie Z. |last4=Reimers |first4=Robert S. |last5=Roy |first5=Chad J. |date=December 2018 |title=Comparative in vitro effectiveness of a novel contact lens multipurpose solution on Acanthamoeba castellanii |journal=Journal of Ophthalmic Inflammation and Infection |volume=8 |issue=1 |pages=19 |doi=10.1186/s12348-018-0161-8 |pmc=6200833 |pmid=30357549 |doi-access=free}}</ref>
[[File:Contact lens case for Hydrogen Peroxide solution showing bubbles.jpg|thumb|upright|Contact lenses soaking in a hydrogen peroxide-based solution.]]
;[[Hydrogen peroxide contact solutions]]
:Hydrogen peroxide can be used to disinfect contact lenses.<ref name="hughes">{{Cite journal |last=Hughes |first=Reanne |last2=Kilvington |first2=Simon |date=July 2001 |title=Comparison of Hydrogen Peroxide Contact Lens Disinfection Systems and Solutions against Acanthamoeba polyphaga |journal=Antimicrobial Agents and Chemotherapy |volume=45 |issue=7 |pages=2038–43 |doi=10.1128/AAC.45.7.2038-2043.2001 |pmc=90597 |pmid=11408220}}</ref>  Care should be taken not to get hydrogen peroxide in the eye because it is very painful and irritating.  With "two-step" products, the hydrogen peroxide must be rinsed away with saline before the lenses may be worn. "One-step" systems allow the hydrogen peroxide to react completely, becoming pure water. Thus "one-step" hydrogen peroxide systems do not require the lenses to be rinsed before insertion, provided the solution has been given enough time to react.
:An exposure time of 2-3 hours to 3% {{chem|H|2|O|2}} (non neutralized solution) is sufficient to kill bacteria, HIV, fungi, and ''Acanthamoeba''.<ref name="Hiti2002">{{Cite journal |last=Hiti |first=K |last2=Walochnik |first2=J |last3=Haller-Schober |first3=EM |last4=Faschinger |first4=C |last5=Aspöck |first5=H |date=1 February 2002 |title=Viability of Acanthamoeba after exposure to a multipurpose disinfecting contact lens solution and two hydrogen peroxide systems |journal=British Journal of Ophthalmology |volume=86 |issue=2 |pages=144–146 |doi=10.1136/bjo.86.2.144 |pmc=1771011 |pmid=11815336}}</ref><ref name="Hiti2004">{{Cite journal |last=Hiti |first=K |last2=Walochnik |first2=J |last3=Faschinger |first3=C |last4=Haller-Schober |first4=E-M |last5=Aspöck |first5=H |date=December 2005 |title=One- and two-step hydrogen peroxide contact lens disinfection solutions against Acanthamoeba: How effective are they? |journal=Eye |volume=19 |issue=12 |pages=1301–1305 |doi=10.1038/sj.eye.6701752 |pmid=15543174 |doi-access=free}}</ref> This can be achieved by using a "two-step" product or a "one-step" tablet system if the catalytic tablet is not added before 2-3 hours.<ref name="Hiti2004" /> However, the "one-step" catalytic disk systems are not effective against ''Acanthamoeba'' due to insufficient exposure time.<ref name="Hiti2004" />
;Enzymatic cleaner
:Used for cleaning protein deposits off lenses, usually weekly, if the daily cleaner is not sufficient. Typically, this cleaner is in tablet form.
;Ultraviolet, vibration, or ultrasonic devices
:These devices intend to disinfect and clean contact lenses. The lenses are inserted inside the portable device (running on batteries and/or plug-in) for 2 to 6 minutes during which both the microorganisms and protein build-up are supposed to be cleaned. However these devices can not be used to replace the manual rub and rinse method because vibration and ultrasound can not create relative motion between contact lens and solution, which is required for proper cleaning of the lens.<ref>{{Cite journal |last=Efron |first=Nathan |last2=Lowe |first2=Russell |last3=Vallas |first3=Vicky |last4=Grusiner |first4=Eugene |date=1991-01-01 |title=Clinical efficacy of standing wave and ultrasound for cleaning and disinfecting contact lenses |url=https://www.contactlensjournal.com/article/0892-8967(91)90040-7/abstract |journal=International Contact Lens Clinic |language=English |volume=18 |issue=1 |pages=24–29 |doi=10.1016/0892-8967(91)90040-7 |issn=0892-8967}}</ref>  These devices are not usually available in optic retailers but are in other stores.<ref>{{Cite journal |date=6 April 2019 |title=How Optical Ultrasonic Cleaners Work |url=http://www.tech-faq.com/how-optical-ultrasonic-cleaners-work.html |website=The Tech-FAQ}}</ref><ref>{{Cite journal |last=White |first=Gina |title=Caring for Soft Contact Lenses |url=http://www.allaboutvision.com/contacts/caresoftlens.htm |website=All About Vision}}</ref><ref>{{Cite journal |last=Ward |first=Michael |title=Soft Contact Lens Care Products |url=http://www.clspectrum.com/article.aspx?article=12384 |website=Contact Lens Spectrum}}</ref>

====Rub and rinse method====
Contact lenses can be mechanically cleaned of more substantial protein, lipid and debris build up by rubbing them between the clean pad of a finger and the palm of a hand, using a small amount of cleaning fluid as a lubricant; and by rinsing thereafter. This "rub and rinse" method is thought to be the most effective method for multipurpose solutions,<ref name="zhuRub">{{Cite journal |last=Zhu |first=Hua |last2=Bandara |first2=Mahesh B. |last3=Vijay |first3=Ajay K. |last4=Masoudi |first4=Simin |last5=Wu |first5=Duojia |last6=Willcox |first6=Mark D. P. |date=August 2011 |title=Importance of Rub and Rinse in Use of Multipurpose Contact Lens Solution |journal=Optometry and Vision Science |volume=88 |issue=8 |pages=967–972 |doi=10.1097/OPX.0b013e31821bf976 |pmid=21623253 |s2cid=23544740 |doi-access=free}}</ref> and is the method indicated by the [[American Academy of Ophthalmology]] regardless of cleaning solution used.<ref name="aaoRub">{{Cite web |last=Boyd |first=Kierstan |date=4 March 2021 |title=How to Take Care of Contact Lenses |url=https://www.aao.org/eye-health/glasses-contacts/contact-lens-care |access-date=5 October 2021 |website=[[American Academy of Ophthalmology|www.aao.org]]}}</ref> In 2010, the FDA recommended that manufacturers removed the "no rub" from product labeling,<ref name="FDAguide">{{Cite web |date=15 August 2010 |title=Contact Lens Care Products Labeling - Guidance for Industry and FDA Staff |url=https://www.fda.gov/medical-devices/guidance-documents-medical-devices-and-radiation-emitting-products/contact-lens-care-products-labeling-guidance-industry-and-fda-staff |access-date=5 October 2021 |website=[[FDA|www.fda.gov]]}}</ref> "because {{'}}rub-and-rinse{{'}} regimens help prevent microbial adhesion to the contact lens, help prevent formation of [[biofilm]]s, and generally reduce the microbial load on the lens and the lens case."<ref name="FDArub">{{Cite web |date=19 May 2009 |title=FDA Letter to Firms with Marketing Clearance for No-rub Multipurpose Contact Lens Solutions |url=https://www.fda.gov/medical-devices/contact-lenses/fda-letter-firms-marketing-clearance-no-rub-multipurpose-contact-lens-solutions |access-date=5 October 2021 |website=[[FDA|www.fda.gov]]}}</ref>

====Physical rubbing devices====
[[File:Eyexpert Supermoist lenzenvloeistof twee maten inclusief lenshouder.jpg|thumb|upright|alt=See caption|Saline solution bottles together with contact lens cases]]

This type of devices mimic digital rubbing. The lenses are sandwiched by silicone parts inside the portable device. The device applies a gentle yet high speed rubbing action on the lens surface and remove debris.

;[[Saline solution]]
:Sterile saline is used for rinsing the lens after cleaning and preparing it for insertion. Saline solutions do not disinfect, so it must be used in conjunction with some type of disinfection system. One advantage to saline is that it cannot cause an allergic response, so it is well suited for individuals with sensitive eyes or strong allergies.
;Daily cleaner
:Used to clean lenses on a daily basis. A few drops of cleaner are applied to the lens while it rests in the palm of the hand; the lens is rubbed for about 20 seconds with a clean fingertip (depending on the product) on each side. Lens must then be rinsed. This system is commonly used to care for rigid lenses.

Water is not recommended for cleaning contact lenses.<ref name="raz">{{Cite journal |last=Razmaria |first=Aria A. |year=2015 |title=Proper Care of Contact Lenses |journal=JAMA |volume=314 |issue=14 |page=1534 |doi=10.1001/jama.2015.12468 |pmid=26462011}}</ref> Insufficiently chlorinated tap water can lead to lens contamination, particularly by Acanthamoeba. On the other hand, sterile water will not kill any contaminants that get in from the environment.<ref name="Carnt">{{Cite journal |last=Carnt |first=Nicole A. |last2=Subedi |first2=Dinesh |last3=Connor |first3=Sophie |last4=Kilvington |first4=Simon |date=11 March 2020 |title=The relationship between environmental sources and the susceptibility of Acanthamoeba keratitis in the United Kingdom |journal=PLOS ONE |volume=15 |issue=3 |pages=e0229681 |bibcode=2020PLoSO..1529681C |doi=10.1371/journal.pone.0229681 |pmc=7065798 |pmid=32160218 |doi-access=free}}</ref>

Aside from cleaning the contact lenses, contact lens case should also be kept clean and be replaced at minimum every 3 months.<ref name="aaoRub" />

Contact lens solutions often contain [[preservative]]s such as [[benzalkonium chloride]] and [[benzyl alcohol]]. Preservative-free products usually have shorter [[shelf life|shelf lives]], but are better suited for individuals with an allergy or sensitivity to a preservative. In the past, [[thiomersal]] was used as a preservative. In 1989, thiomersal was responsible for about 10% of problems related to contact lenses.<ref>{{Cite journal |last=Wilson-Holt |first=N |last2=Dart |first2=J K G |date=September 1989 |title=Thiomersal keratoconjunctivitis, frequency, clinical spectrum and diagnosis |journal=Eye |volume=3 |issue=5 |pages=581–587 |doi=10.1038/eye.1989.91 |pmid=2630335 |doi-access=free}}</ref> As a result, most products no longer contain thiomersal.