View source for LASIK

{{Short description|Corrective ophthalmological surgery}}
{{Distinguish|Lasic (disambiguation){{!}}Lasic|Lassik (disambiguation){{!}}Lassik}}
{{For-multi|the drug used for hypertension|Lasix|the Slovakian footballer|Richard Lásik}}
{{Use dmy dates|date=September 2024}}
{{cs1 config |name-list-style=vanc |display-authors=6}}
{{Infobox medical intervention
|  Name        = LASIK
|  Image       = US Navy 070501-N-5319A-007 Capt. Joseph Pasternak, an ophthalmology surgeon at National Naval Medical Center Bethesda, lines up the laser on Marine Corps Lt. Col. Lawrence Ryder's eye before beginning LASIK IntraLase surgery.jpg
|  Caption     = LASIK surgery using an [[excimer laser]] at [[Walter Reed National Military Medical Center|US National Naval Medical Center Bethesda]]
| field        = [[Ophthalmology]], [[optometry]]
|  ICD10       =
|  ICD9        = {{ICD9proc|11.71}}
|  MeshID      = D020731
|  OPS301      =
|  MedlinePlus = 007018
|  OtherCodes  =
}}

'''LASIK''' or '''Lasik''' ({{IPAc-en|ˈ|l|eɪ|s|ɪ|k}}; "[[laser]]-assisted [[in situ]] [[keratomileusis]]"), commonly referred to as '''laser eye surgery''' or '''laser vision correction''', is a type of [[refractive surgery]] for the correction of [[myopia]], [[hyperopia]], and [[astigmatism (eye)|astigmatism]].<ref name="NYT-20180611" /> LASIK surgery is performed by an [[ophthalmology|ophthalmologist]] who uses a [[femtosecond laser]] or a [[microkeratome]] to create a corneal flap to expose the [[corneal stroma]] and then an [[excimer laser]] to reshape the corneal stroma in order to improve [[visual acuity]].<ref name="LASIK FDA">{{cite web |title=LASIK |url=https://www.fda.gov/medical-devices/surgery-devices/lasik |website=U.S. [[Food and Drug Administration]] (FDA) |access-date=15 August 2024 |date=13 June 2023 |archive-date=20 May 2024 |archive-url=https://web.archive.org/web/20240520033718/https://www.fda.gov/medical-devices/surgery-devices/lasik |url-status=live }}</ref><ref name="Finn">{{cite news | url=https://www.washingtonpost.com/national/health-science/medical-mystery-preparation-for-surgery-revealed-cause-of-deteriorating-eyesight/2011/11/26/gIQAwVLj4O_story.html | newspaper=[[The Washington Post]] | first=Peter | last=Finn | date=20 December 2012 | title=Medical Mystery: Preparation for surgery revealed cause of deteriorating eyesight | access-date=2 September 2017 | archive-date=15 June 2018 | archive-url=https://web.archive.org/web/20180615164807/https://www.washingtonpost.com/national/health-science/medical-mystery-preparation-for-surgery-revealed-cause-of-deteriorating-eyesight/2011/11/26/gIQAwVLj4O_story.html | url-status=live }}</ref>

LASIK is very similar to another surgical corrective procedure, [[photorefractive keratectomy]] (PRK), and [[Photorefractive keratectomy#LASEK|LASEK]]. All represent advances over [[radial keratotomy]] in the surgical treatment of [[refractive error]]s of vision. For people with moderate to high [[myopia]] or thin [[cornea]]s which cannot be treated with LASIK or PRK, the [[phakic intraocular lens]] is an alternative.<ref name=lovisolo>{{cite journal | vauthors = Lovisolo CF, Reinstein DZ | title = Phakic intraocular lenses | journal = Survey of Ophthalmology | volume = 50 | issue = 6 | pages = 549–87 | date = Nov–Dec 2005 | pmid = 16263370 | doi = 10.1016/j.survophthal.2005.08.011 }}</ref><ref>{{cite journal | vauthors = Sanders DR, Vukich JA | title = Comparison of implantable contact lens and laser assisted in situ keratomileusis for moderate to high myopia | journal = Cornea | volume = 22 | issue = 4 | pages = 324–31 | date = May 2003 | pmid = 12792475 | doi = 10.1097/00003226-200305000-00009 | s2cid = 21142105 }}</ref>

As of 2018, roughly 9.5 million Americans have had LASIK<ref name="NYT-20180611">{{cite news |last=Rabin |first=Roni Caryn |title=Lasik's Risks Are Coming Into Sharper Focus – Some patients who undergo the eye surgery report a variety of side effects. They may persist for years, studies show. |url=https://www.nytimes.com/2018/06/11/well/lasik-complications-vision.html |date=11 June 2018 |work=[[The New York Times]] |access-date=11 June 2018 |archive-date=26 May 2023 |archive-url=https://web.archive.org/web/20230526183146/https://www.nytimes.com/2018/06/11/well/lasik-complications-vision.html |url-status=live }}</ref><ref>{{cite web|url=http://bmctoday.net/crstodayeurope/2013/02/article.asp?f=ndyag-treatment-of-epithelial-ingrowth|title=Nd:YAG Treatment of Epithelial Ingrowth |first1=Dan |last1=Lindfield |first2=Tom |last2=Poole |publisher=Cataract and Refractive Surgery Today|access-date=12 September 2013| archive-url=https://web.archive.org/web/20131105095141/http://bmctoday.net/crstodayeurope/2013/02/article.asp?f=ndyag-treatment-of-epithelial-ingrowth | archive-date=5 November 2013 | url-status=dead }}</ref> and, globally, between 1991 and 2016, more than 40 million procedures were performed.<ref name="EW-20160401">{{cite web |last=Stodola |first=Ellen |title=LASIK worldwide |url=https://www.eyeworld.org/article-lasik-worldwide |date=1 April 2016 |work=EyeWorld.org |access-date=12 June 2018 |archive-date=12 June 2018 |archive-url=https://web.archive.org/web/20180612162458/https://www.eyeworld.org/article-lasik-worldwide |url-status=dead }}</ref><ref>{{cite magazine | last=Stuart | first=Annie |url=https://www.aao.org/eyenet/article/look-at-lasik-past-present-future |title=A Look at LASIK Past, Present and Future|magazine=EyeNet Magazine |access-date=12 September 2013|url-status=live|archive-url=https://web.archive.org/web/20130731030413/http://www.aao.org/publications/eyenet/200906/feature.cfm|archive-date=31 July 2013}}</ref> However, the procedure seemed to be a declining option as of 2015.<ref name=":0">{{cite journal | vauthors = Corcoran KJ | title = Macroeconomic landscape of refractive surgery in the United States | journal = Current Opinion in Ophthalmology | volume = 26 | issue = 4 | pages = 249–54 | date = July 2015 | pmid = 26058020 | doi = 10.1097/ICU.0000000000000159 | s2cid = 11842503 }}</ref>
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== Process ==
In March 2009, the FDA officially recognized the new LASIK standard from The American National Standards Institute (ANSI), entitled "Laser Systems for Corneal Reshaping".<ref>{{cite web |last1=Health |first1=Center for Devices and Radiological |title=The FDA's LASIK Program |url=https://www.fda.gov/medical-devices/lasik/fdas-lasik-program |website=FDA |access-date=9 December 2024 |language=en |date=18 August 2023}}{{dead link|date=May 2025|bot=medic}}{{cbignore|bot=medic}}</ref>

A detailed pre-operative screening will assess corneal thickness, shape, and refractive error, ensuring the patient is a suitable candidate. During the surgery, a surgeon uses a femtosecond laser or a microkeratome blade to create a thin corneal flap, which is then carefully folded back to expose the underlying tissue. An excimer laser precisely reshapes the stromal layer of the cornea, removing microscopic amounts of tissue to correct refractive errors. This step is guided by a pre-determined surgical plan tailored to the patient's specific visual needs. After the cornea is reshaped, the flap is repositioned, serving as a natural bandage that adheres without the need for stitches. The entire procedure typically takes 10–15 minutes per eye and offers minimal discomfort and rapid recovery, allowing most patients to return to normal activities within a day or two.{{citation needed|date=September 2024}}

=== Preoperative procedures ===

==== Pre-operative examination and education ====
In the United States, the US [[Food and Drug Administration]] (FDA) has approved LASIK for people 18 years of age and older, but the [[American Academy of Ophthalmology]] recommends people wait until age 21 because vision needs to stabilize.<ref name="FDA L">{{Cite web |date=7 November 2018 |title=When is LASIK not for me? |url=https://www.fda.gov/medical-devices/lasik/when-lasik-not-me |website=U.S. [[Food and Drug Administration]] (FDA) |access-date=16 December 2019 |archive-date=19 September 2019 |archive-url=https://web.archive.org/web/20190919022717/https://www.fda.gov/medical-devices/lasik/when-lasik-not-me |url-status=live }}</ref><ref>{{Cite web |last=Boyd |first=Kierstan |date=9 August 2024 |title=LASIK — Laser Eye Surgery |url=https://www.aao.org/eye-health/treatments/lasik |access-date=14 September 2024 |website=American Academy of Ophthalmology |archive-date=18 January 2024 |archive-url=https://web.archive.org/web/20240118162254/https://www.aao.org/eye-health/treatments/lasik |url-status=live }}</ref> More importantly the patient's eye prescription should be stable for at least one year prior to surgery.
The patient may be examined with pupillary dilation and education given prior to the procedure. Before the surgery, the patient's [[cornea]]s are examined with a [[Corneal pachymetry|pachymeter]] to determine their thickness, and with a topographer, or corneal topography machine,<ref name="Finn" /> to measure their surface contour. Using low-power [[laser]]s, a topographer creates a [[topographic map]] of the cornea. The procedure is contraindicated if the topographer finds difficulties such as [[keratoconus]]<ref name="Finn" /> The preparatory process also detects [[Astigmatism (eye)|astigmatism]] and other irregularities in the shape of the cornea. Using this information, the surgeon calculates the amount and the location of corneal tissue to be removed. The patient is prescribed and self-administers an antibiotic beforehand to minimize the risk of infection after the procedure and is sometimes offered a short acting oral sedative medication as a pre-medication. Prior to the procedure, anaesthetic eye drops are instilled. Factors that may rule out LASIK for some patients include large pupils, thin corneas and extremely dry eyes.<ref>{{cite web|url=https://www.tlcvision.com/lasik-candidate/|title=Am I a Candidate For LASIK Surgery? TLC Laser Eye Centers|website=Tlcvision.com|access-date=20 December 2018|archive-date=15 September 2024|archive-url=https://web.archive.org/web/20240915032433/https://www.tlcvision.com/lasik-candidate/|url-status=live}}</ref>

=== Operative procedure ===

LASIK permanently changes the shape of the cornea, the clear covering of the front of the eye, using an [[excimer laser]]. A mechanical microkeratome (a blade device) or a laser keratome ([[femtosecond laser]]) is used to cut a flap in the cornea. A hinge is left at one end of this flap. The flap is folded back revealing the [[corneal stroma]], the middle section of the cornea. Pulses from a computer-controlled laser (excimer laser) vaporize a portion of the stroma and the flap is replaced.<ref name="LASIK FDA"/>

Performing the laser ablation in the deeper corneal stroma provides for more rapid visual recovery and less pain than the earlier technique, [[photorefractive keratectomy]] (PRK).<ref>{{cite journal | vauthors = Shortt AJ, Allan BD, Evans JR | title = Laser-assisted in-situ keratomileusis (LASIK) versus photorefractive keratectomy (PRK) for myopia | journal = The Cochrane Database of Systematic Reviews | volume = 1 | issue = 1 | pages = CD005135 | date = January 2013 | pmid = 23440799 | doi = 10.1002/14651858.CD005135.pub3 | quote = There was evidence that LASIK gives a faster visual recovery than PRK and is a less painful technique. Results at one year after surgery were comparable: most analyses favoured LASIK but they were not statistically significant. | pmc = 11848121 }}</ref>

=== Postoperative care ===
Patients are usually given a course of antibiotic and anti-inflammatory eye drops. These are continued in the weeks following surgery. Patients are told to rest and are given dark eyeglasses to protect their eyes from bright lights and occasionally protective goggles to prevent rubbing of the eyes when asleep and to reduce dry eyes. They also are required to moisturize the eyes with preservative-free tears and follow directions for prescription drops. Occasionally after the procedure a bandage contact lens is placed to aid the healing, and typically removed after 3–4 days. Patients should be adequately informed by their surgeons of the importance of proper post-operative care to minimize the risk of complications.<ref name="dta">{{cite book| first1 = Dimitri T. | last1 = Azar | first2 = Damien | last2 = Gatinel |title=Refractive surgery|year=2007|publisher=Mosby Elsevier|location=Philadelphia|isbn=978-0-323-03599-6|edition=2nd}}</ref>

=== Wavefront-guided ===
Wavefront-guided LASIK is a variation of LASIK surgery in which, rather than applying a simple correction of only long/short-sightedness and astigmatism (only lower order aberrations as in traditional LASIK), an [[ophthalmologist]] applies a spatially varying correction, guiding the computer-controlled excimer laser with measurements from a [[wavefront]] sensor. The goal is to achieve a more optically perfect eye, though the result still depends on the physician's success at predicting changes that occur during healing and other factors that may have to do with the regularity/irregularity of the cornea and the axis of any residual astigmatism. Another important factor is whether the excimer laser can correctly register eye position in 3 dimensions, and to track the eye in all the possible directions of eye movement. If a wavefront guided treatment is performed with less than perfect registration and tracking, pre-existing aberrations can be worsened. In older patients, [[scattering]] from microscopic particles ([[cataract]] or incipient cataract) may play a role that outweighs any benefit from wavefront correction.<ref name="Walsh2000A">Walsh MJ. Is the future of refractive surgery based on corneal topography or wavefront? "Ocular Surgery News". 1 August 2000, page 26.</ref><ref name="Walsh2000">Walsh MJ. Wavefront is showing signs of success, but can it do it alone? ''Ocular Surgery News''. 1 September 2000, page 41.</ref><ref name="EW2000">EW Dialogue: the future of wavefront refraction as a diagnostic tool. "EyeWorld". May 2000, pages 64 and 65.</ref><ref name="Alpins2002Fail">{{cite journal | vauthors = Alpins NA | title = Wavefront technology: a new advance that fails to answer old questions on corneal vs. refractive astigmatism correction | journal = Journal of Refractive Surgery | volume = 18 | issue = 6 | pages = 737–9 | year = 2002 | doi = 10.3928/1081-597X-20021101-12 | pmid = 12458868 }}</ref>

When treating a patient with preexisting astigmatism, most wavefront-guided LASIK lasers are designed to treat regular astigmatism as determined externally by [[corneal topography]]. In patients who have an element of internally induced astigmatism, therefore, the wavefront-guided astigmatism correction may leave regular astigmatism behind (a cross-cylinder effect). If the patient has preexisting irregular astigmatism, wavefront-guided approaches may leave both regular and irregular astigmatism behind. This can result in less-than-optimal visual acuity compared with a wavefront-guided approach combined with vector planning, as shown in a 2008 study.<ref name="Alpins2008">{{cite journal | vauthors = Alpins N, Stamatelatos G | title = Clinical outcomes of laser in situ keratomileusis using combined topography and refractive wavefront treatments for myopic astigmatism | journal = Journal of Cataract and Refractive Surgery | volume = 34 | issue = 8 | pages = 1250–9 | date = August 2008 | pmid = 18655973 | doi = 10.1016/j.jcrs.2008.03.028 | s2cid = 29819060 }}</ref>

The "leftover" astigmatism after a purely surface-guided laser correction can be calculated beforehand, and is called ocular residual astigmatism (ORA). ORA is a calculation of astigmatism due to the noncorneal surface (internal) optics. The purely refraction-based approach represented by wavefront analysis actually conflicts with corneal surgical experience developed over many years.<ref name="Alpins2002Fail" />

The pathway to "super vision" thus may require a more customized approach to corneal astigmatism than is usually attempted, and any remaining astigmatism ought to be regular (as opposed to irregular), which are both fundamental principles of vector planning overlooked by a purely wavefront-guided treatment plan.<ref name="Alpins2002Fail" /> This was confirmed by the 2008 study mentioned above, which found a greater reduction in corneal astigmatism and better visual outcomes under [[mesopic vision|mesopic conditions]] using wavefront technology combined with vector analysis than using wavefront technology alone, and also found equivalent higher-order aberrations (see [[#Higher-order aberrations|below]]).<ref name="Alpins2008" /> Vector planning also proved advantageous in patients with [[keratoconus]].<ref name="Alpins2007">{{cite journal | vauthors = Alpins N, Stamatelatos G | title = Customized photoastigmatic refractive keratectomy using combined topographic and refractive data for myopia and astigmatism in eyes with forme fruste and mild keratoconus | journal = Journal of Cataract and Refractive Surgery | volume = 33 | issue = 4 | pages = 591–602 | date = April 2007 | pmid = 17397730 | doi = 10.1016/j.jcrs.2006.12.014 | s2cid = 14881153 }}</ref>

No good data can be found that compare the percentage of LASIK procedures that employ wavefront guidance versus the percentage that do not, nor the percentage of refractive surgeons who have a preference one way or the other. Wavefront technology continues to be positioned as an "advance" in LASIK with putative advantages;<ref name="AAOGuide">{{cite web | publisher=American Academy of Ophthalmology | url=https://the-eye.eu/public/Site-Dumps/campdivision.com/camp/Text%20Files/PDF/To%20be%20organized/pdf/LASER_Surg_LASIK_SWGuideNewsroom.pdf | title=Refractive Laser Surgery: An In-Depth Look at LASIK and Brief Overview of PRK, Epi-LASIK, and LASEK: A Science Writer's Guide | archive-url=https://web.archive.org/web/20120616143123/http://www.aao.org/newsroom/guide/upload/LASER_Surg_LASIK_SWGuideNewsroom.pdf | archive-date=16 June 2012 | access-date=29 January 2012 | url-status=live }}</ref> however, it is clear that not all LASIK procedures are performed with wavefront guidance.<ref>{{cite web | first = Liz | last = Segre | url = http://www.allaboutvision.com/visionsurgery/cost.htm | title = Cost of LASIK eye surgery and other corrective procedures | website = Allaboutvision.com | access-date = 15 August 2012 | archive-date = 19 June 2012 | archive-url = https://web.archive.org/web/20120619144048/http://www.allaboutvision.com/visionsurgery/cost.htm | url-status = live }}</ref>{{Unreliable source?|date=September 2024|reason=blog}}

Still, surgeons claim patients are generally more satisfied with this technique than with previous methods, particularly regarding lowered incidence of "halos", the visual artifact caused by [[spherical aberration]] induced in the eye by earlier methods. A meta-analysis of eight trials showed a lower incidence of these higher order aberrations in patients who had wavefront-guided LASIK compared to non-wavefront-guided LASIK.<ref>{{cite journal | vauthors = Fares U, Suleman H, Al-Aqaba MA, Otri AM, Said DG, Dua HS | title = Efficacy, predictability, and safety of wavefront-guided refractive laser treatment: metaanalysis | journal = Journal of Cataract and Refractive Surgery | volume = 37 | issue = 8 | pages = 1465–75 | date = August 2011 | pmid = 21782089 | doi = 10.1016/j.jcrs.2011.02.029 | s2cid = 26968756 }}</ref> Based on their experience, the United States Air Force has described WFG-Lasik as giving "superior vision results".<ref>{{cite web| first = Sue | last = Campbell |url=https://www.af.mil/News/Article-Display/Article/135619/air-force-aims-for-weapons-grade-vision/ |title=Air Force aims for 'weapons-grade' vision |website=United States Air Force | date=12 November 2004 |access-date=10 December 2011 |archive-url=https://archive.today/20120728134939/http://www.af.mil/news/story.asp?storyID=123009161 |archive-date=28 July 2012 |url-status=live }}</ref>

=== Topography-assisted ===
Topography-assisted LASIK is intended to be an advancement in precision and reduce night-vision side effects. The first topography-assisted device received FDA approval 13 September 2013.<ref name="FDA-Nidek-EC-5000">{{cite web|url=https://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DeviceApprovalsandClearances/Recently-ApprovedDevices/ucm372986.htm|publisher=U.S. [[Food and Drug Administration]] (FDA)|title=Nidek EC-5000 Excimer Laser System – P970053/S011|date=13 October 2013|access-date=1 May 2016|archive-date=3 June 2016|archive-url=https://web.archive.org/web/20160603201859/http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DeviceApprovalsandClearances/Recently-ApprovedDevices/ucm372986.htm|url-status=dead}}</ref><ref>{{cite web |url=http://eyeworld.org/supplements/April2014/Monday_Alcon%20supplement-Boston%202014_Web.pdf|title=Topography-guided LASIK: A paradigm shift in refractive laser treatment|publisher=EyeWorld Daily News| first = Doyle | last = Stulting |date=28 April 2014|access-date=1 May 2016}}</ref>

== History ==

=== Barraquer's early work ===
In the 1950s, the [[microkeratome]] and [[keratomileusis]] technique were developed in [[Bogotá]], Colombia, by the [[Spain|Spanish]] ophthalmologist [[Jose Barraquer|José Barraquer]]. In his clinic, he would cut thin (one hundredth of a mm thick) flaps in the [[cornea]] to alter its shape. Barraquer also investigated how much of the cornea had to be left unaltered in order to provide stable long-term results.<ref>{{cite journal | vauthors = Troutman RC, Swinger C | title = Refractive keratoplasty: keratophakia and keratomileusis | journal = Transactions of the American Ophthalmological Society | volume = 76 | pages = 329–39 | year = 1978 | pmid = 382579 | pmc = 1311630 }}</ref>

=== Laser refractive surgery ===
In 1980, [[Rangaswamy Srinivasan]], [[Samuel E. Blum]], and [[James J. Wynne]] at the [[IBM Research]] laboratory, discovered that an ultraviolet excimer laser could etch living tissue, with precision and with no thermal damage to the surrounding area. The phenomenon was termed "ablative photo-decomposition" (APD).<ref>{{cite web |url=http://www.aip.org/ca/srinivasan.html |title=Prize for the Industrial Application of Physics Winner |website=American Institute of Physics |access-date=10 December 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110928093030/http://www.aip.org/ca/srinivasan.html |archive-date=28 September 2011 }}</ref><ref>{{cite web | title=James Wynne | url=https://laserfest.org/lasers/pioneers/wynne.cfm | website=laserfest.org | access-date=30 December 2021 | archive-date=5 February 2023 | archive-url=https://web.archive.org/web/20230205044704/https://laserfest.org/lasers/pioneers/wynne.cfm | url-status=dead }}</ref>
Five years later, in 1985, Steven Trokel at the Edward S. Harkness Eye Institute, [[Columbia University]] in New York City, published his work using the excimer laser in radial keratotomy. He wrote,
:"The central corneal flattening obtained by radial diamond knife incisions has been duplicated by radial laser incisions in 18 enucleated human eyes. The incisions, made by 193 nm far-ultraviolet light radiation emitted by the excimer laser, produced corneal flattening ranging from 0.12 to 5.35 diopters. Both the depth of the corneal incisions and the degree of central corneal flattening correlated with the laser energy applied. Histopathology revealed the remarkably smooth edges of the laser incisions."<ref>{{cite journal | vauthors = Cotliar AM, Schubert HD, Mandel ER, Trokel SL | title = Excimer laser radial keratotomy | journal = Ophthalmology | volume = 92 | issue = 2 | pages = 206–8 | date = February 1985 | pmid = 3982798 | doi = 10.1016/s0161-6420(85)34052-6 }}</ref>

=== Patent ===
A number of patents have been issued for several techniques related to LASIK. Rangaswamy Srinivasan and James Wynne filed a patent application on the [[ultraviolet]] [[excimer laser]], in 1986, issued in 1988.<ref name="Blum">{{cite patent | number=US4784135 | title= Far ultraviolet surgical and dental procedures| gdate =1988-11-15 | fdate=1982-12-09 | inventor = Samuel E. Blum, Rangaswamy Srinivasan, James J. Wynne}}</ref> In 1989, [[Gholam A. Peyman]] was granted a US patent for using an excimer laser to modify corneal curvature.<ref>{{cite patent | gdate =1988-06-20 | fdate=1988-01-22 | inventor = Gholam A. Peyman | title=Method for modifying corneal curvature | number=US4840175}}</ref> It was,
:"A method and apparatus for modifying the curvature of a live cornea via use of an excimer laser. The live cornea has a thin layer removed therefrom, leaving an exposed internal surface thereon. Then, either the surface or thin layer is exposed to the laser beam along a predetermined pattern to ablate desired portions. The thin layer is then replaced onto the surface. Ablating a central area of the surface or thin layer makes the cornea less curved, while ablating an annular area spaced from the center of the surface or layer makes the cornea more curved. The desired predetermined pattern is formed by use of a variable diaphragm, a rotating orifice of variable size, a movable mirror or a movable fiber optic cable through which the laser beam is directed towards the exposed internal surface or removed thin layer."<ref name="Blum" />
The patents related to so-called broad-beam LASIK and PRK technologies were granted to US companies including Visx and Summit during 1990–1995 based on the fundamental US patent issued to IBM (1988) which claimed the use of UV laser for the ablation of organic tissues.<ref name="Blum" />

=== Implementation in the United States ===
The LASIK technique was implemented in the US after its successful application elsewhere. The [[Food and Drug Administration]] (FDA) commenced a trial of the excimer laser in 1989. The first enterprise to receive FDA approval to use an excimer laser for photo-refractive keratectomy was Summit Technology.<ref name="fda.gov">{{cite web |url=https://www.fda.gov/medical-devices/lasik/fda-approved-lasers-prk-and-other-refractive-surgeries |title=FDA-Approved Lasers for PRK and Other Refractive Surgeries |website=U.S. [[Food and Drug Administration]] (FDA) |access-date=10 December 2011 |archive-date=14 September 2024 |archive-url=https://web.archive.org/web/20240914194129/https://www.fda.gov/medical-devices/lasik/fda-approved-lasers-prk-and-other-refractive-surgeries |url-status=live }}</ref>
In 1992, under the direction of the FDA, Greek ophthalmologist [[Ioannis Pallikaris]] introduced LASIK to ten VISX centers. In 1998, the "Kremer Excimer Laser", serial number KEA 940202, received FDA approval for its singular use for performing LASIK.<ref name="Reference A">{{cite web |url=https://www.fda.gov/medical-devices/lasik/list-fda-approved-lasers-lasik |title=List of FDA-Approved Lasers for LASIK |website=U.S. [[Food and Drug Administration]] (FDA) |access-date=10 December 2011 |archive-date=14 September 2024 |archive-url=https://web.archive.org/web/20240914194129/https://www.fda.gov/medical-devices/lasik/list-fda-approved-lasers-lasik |url-status=live }}</ref> Subsequently, Summit Technology was the first company to receive FDA approval to mass manufacture and distribute excimer lasers. VISX and other companies followed.<ref name="Reference A" />
[[File:MEL60-UOC.jpg|thumb|The excimer laser that was used for the first LASIK surgeries by I. Pallikaris]] [[Ioannis Pallikaris|Pallikaris]] suggested a flap of cornea could be raised by microkeratome prior to the performing of PRK with the excimer laser. The addition of a flap to PRK became known as LASIK. The use of a femtosecond laser to raise the flap of cornea was discovered after a graduate student at the [[University of Michigan]] suffered an accidental laser eye injury in 1993. Tibor Juhasz and Ron Kurtz developed this approach and went on to found [[IntraLase]] to perform bladeless LASIK surgery.<ref name="nsf.gov">{{cite web |url=https://new.nsf.gov/science-matters/invention-impact-story-lasik-eye-surgery |title=Invention to Impact: The story of LASIK eye surgery |website=U.S. [[National Science Foundation]] (NSF) |date=15 March 2024 |access-date=15 October 2024  }}</ref>

=== Recent years ===
The procedure seems to be a declining option for many in the United States, dropping more than 50 percent, from about 1.5 million surgeries in 2007 to 604,000 in 2015, according to the eye-care data source Market Scope.<ref>{{cite news|last1=Schoenberg|first1=Nara|date=23 May 2016|title=Lasik surgery falling out of favor with patients|url=http://www.chicagotribune.com/lifestyles/health/sc-lasik-loses-luster-health-0525-20160526-story.html|newspaper=Chicago Tribune|access-date=15 June 2018|archive-date=15 June 2018|archive-url=https://web.archive.org/web/20180615163318/http://www.chicagotribune.com/lifestyles/health/sc-lasik-loses-luster-health-0525-20160526-story.html|url-status=live}}</ref> A study determined the frequency with which LASIK was searched on Google from 2007 to 2011.<ref name="stein etal">{{cite journal|vauthors=Stein JD, Childers DM, Nan B, Mian SI|date=July 2013|title=Gauging interest of the general public in laser-assisted in situ keratomileusis eye surgery|journal=Cornea|volume=32|issue=7|pages=1015–8|doi=10.1097/ICO.0b013e318283c85a|pmc=3679260|pmid=23538615}}</ref> Within this time frame, LASIK searches declined by 40% in the United States.<ref name="stein etal" /> Countries such as the U.K. and India also showed a decline, 22% and 24% respectively.<ref name="stein etal" /> Canada, however, showed an increase in LASIK searches by 8%.<ref name="stein etal" /> This decrease in interest can be attributed to several factors: the emergence of [[Refractive surgery|refractive cataract surgery]], the economic recession in 2008, and unfavorable media coverage from the FDA's 2008 press release on LASIK.<ref name=":0" />

== Effectiveness ==
In 2006, the British [[National Health Service]]'s [[National Institute for Health and Clinical Excellence]] (NICE) considered evidence of the effectiveness and the potential risks of the laser surgery, stating "current evidence suggests that photorefractive (laser) surgery for the correction of refractive errors is safe and effective for use in appropriately selected patients. Clinicians undertaking photorefractive (laser) surgery for the correction of refractive errors should ensure that patients understand the benefits and potential risks of the procedure. Risks include failure to achieve the expected improvement in unaided vision, development of new visual disturbances, corneal infection and flap complications. These risks should be weighed against those of wearing spectacles or contact lenses."<ref name="nice-guidance">{{cite web |date=March 2006 |title=Photorefractive (laser) surgery for the correction of refractive errors |url=http://www.nice.org.uk/guidance/IPG164/chapter/1-Guidance |publisher=National Health Service |format=pdf |access-date=21 September 2014 |archive-date=22 November 2014 |archive-url=https://web.archive.org/web/20141122125313/http://www.nice.org.uk/guidance/IPG164/chapter/1-Guidance |url-status=live }}</ref> The FDA reports "The safety and effectiveness of refractive procedures has not been determined in patients with some diseases."<ref name="FDA L"/>

=== Satisfaction ===
Surveys of LASIK surgery find rates of patient satisfaction between 92 and 98 percent.<ref name="Saragoussi">{{cite journal |vauthors=Saragoussi D, Saragoussi JJ |date=September 2004 |title=[Lasik, PRK and quality of vision: a study of prognostic factors and a satisfaction survey] |url=http://www.masson.fr/masson/MDOI-JFO-09-2004-27-7-0181-5512-101019-ART3 |journal=Journal Français d'Ophtalmologie |language=fr |volume=27 |issue=7 |pages=755–64 |doi=10.1016/S0181-5512(04)96210-9 |pmid=15499272 |access-date=10 July 2009 |archive-date=17 August 2011 |archive-url=https://web.archive.org/web/20110817001958/http://www.em-consulte.com/article/112864 |url-status=live |url-access=subscription }}</ref><ref name="Bailey">{{cite journal |vauthors=Bailey MD, Mitchell GL, Dhaliwal DK, Boxer Wachler BS, Zadnik K |date=July 2003 |title=Patient satisfaction and visual symptoms after laser in situ keratomileusis |journal=Ophthalmology |volume=110 |issue=7 |pages=1371–8 |doi=10.1016/S0161-6420(03)00455-X |pmid=12867394}}</ref><ref name="McGhee">{{cite journal |vauthors=McGhee CN, Craig JP, Sachdev N, Weed KH, Brown AD | author-link2 = Jennifer Craig (academic) |date=April 2000 |title=Functional, psychological, and satisfaction outcomes of laser in situ keratomileusis for high myopia |journal=Journal of Cataract and Refractive Surgery |volume=26 |issue=4 |pages=497–509 |doi=10.1016/S0886-3350(00)00312-6 |pmid=10771222 |s2cid=13304987}}</ref> In March 2008, the [[American Society of Cataract and Refractive Surgery]] published a patient satisfaction meta-analysis of over 3,000 peer-reviewed articles from international clinical journals. Data from a systematic literature review conducted from 1988 to 2008, consisting of 309 peer-reviewed articles about "properly conducted, well-designed, randomized clinical trials" found a 95.4 percent patient satisfaction rate among LASIK patients.<ref>{{cite journal |vauthors=Solomon KD, Fernández de Castro LE, Sandoval HP, Biber JM, Groat B, Neff KD, Ying MS, French JW, Donnenfeld ED, Lindstrom RL |date=April 2009 |title=LASIK world literature review: quality of life and patient satisfaction |journal=Ophthalmology |volume=116 |issue=4 |pages=691–701 |doi=10.1016/j.ophtha.2008.12.037 |pmid=19344821}}</ref>

A 2017 study claims that overall, preoperative symptoms decreased significantly, and visual acuity excelled. A meta-analysis discovered that 97% of patients achieved uncorrected visual acuity (UCVA) of 20/40, while 62% achieved 20/20.<ref>{{cite journal |vauthors=Sugar A, Hood CT, Mian SI |date=January 2017 |title=Patient-Reported Outcomes Following LASIK: Quality of Life in the PROWL Studies |journal=JAMA |volume=317 |issue=2 |pages=204–205 |doi=10.1001/jama.2016.19323 |pmid=28097345}}</ref>

=== Dissatisfaction ===
Some people with poor outcomes from LASIK surgical procedures report a significantly reduced [[quality of life]] because of vision problems or pain associated with the surgery.<ref name="NYT-20180611" /> A small percentage of patients may need further surgery because their condition is over- or under-corrected. Some patients need to wear contact lenses or glasses even after treatment.<ref name="HNYT">{{cite news |title=LASIK Eye Surgery |newspaper=[[The New York Times]] |url=http://health.nytimes.com/health/guides/surgery/lasik-eye-surgery/overview.html |access-date=10 September 2013 |archive-date=14 September 2024 |archive-url=https://web.archive.org/web/20240914194310/https://www.nytimes.com/section/well |url-status=live }}</ref>

The most common reason for dissatisfaction in LASIK patients is chronic severe [[Dry eye syndrome|dry eye]]. Independent research indicates 95% of patients experience dry eye in the initial post-operative period. This number has been reported to up to 60% after one month. Symptoms begin to improve in the vast majority of patients in the 6 to 12 months following the surgery.<ref>{{cite journal |vauthors=Shtein RM |date=October 2011 |title=Post-LASIK dry eye |journal=Expert Review of Ophthalmology |volume=6 |issue=5 |pages=575–582 |doi=10.1586/eop.11.56 |pmc=3235707 |pmid=22174730}}</ref> However, 30% of post-LASIK referrals to tertiary ophthalmology care centers have been shown to be due to chronic dry eye.<ref>{{cite journal |vauthors=Levinson BA, Rapuano CJ, Cohen EJ, Hammersmith KM, Ayres BD, Laibson PR |date=January 2008 |title=Referrals to the Wills Eye Institute Cornea Service after laser in situ keratomileusis: reasons for patient dissatisfaction |journal=Journal of Cataract and Refractive Surgery |volume=34 |issue=1 |pages=32–9 |doi=10.1016/j.jcrs.2007.08.028 |pmid=18165078 |s2cid=11133295}}</ref><ref>{{cite journal |vauthors=Jabbur NS, Sakatani K, O'Brien TP |date=September 2004 |title=Survey of complications and recommendations for management in dissatisfied patients seeking a consultation after refractive surgery |journal=Journal of Cataract and Refractive Surgery |volume=30 |issue=9 |pages=1867–74 |doi=10.1016/j.jcrs.2004.01.020 |pmid=15342048 |s2cid=25054973}}</ref>

Morris Waxler, a former FDA official who was involved in the approval of LASIK, subsequently criticized its widespread use. In 2010, Waxler made media appearances and claimed that the procedure had a failure rate greater than 50%. The FDA responded that Waxler's information was "filled with false statements, incorrect citations" and "mischaracterization of results".<ref name="waxler-fda">{{cite journal |last=Rodemich |first=Karen |year=2010 |title=Former FDA official warns of LASIK risks: the man who OK'd LASIK now warns of an "epidemic" of eye problems |journal=Review of Optometry |volume=147 |issue=10 |page=4}}</ref>

=== Presbyopia ===
A type of LASIK, known as presbyLasik, may be used in [[presbyopia]]. Results are, however, more variable and some people have a decrease in [[visual acuity]].<ref>{{cite journal |vauthors=Pallikaris IG, Panagopoulou SI |date=July 2015 |title=PresbyLASIK approach for the correction of presbyopia |journal=Current Opinion in Ophthalmology |volume=26 |issue=4 |pages=265–72 |doi=10.1097/icu.0000000000000162 |pmid=26058023 |s2cid=35434343}}</ref>

== Risks ==

=== Dry eyes ===
95% of patients report dry-eye symptoms after LASIK.<ref name="NYT-20180611" /><ref name="nhs">{{cite web |date=5 March 2012 |title=Laser eye surgery and lens surgery |url=https://www.nhs.uk/conditions/laser-eye-surgery-and-lens-surgery/ |access-date=26 October 2013 |publisher=NHS Choices |archive-date=14 September 2024 |archive-url=https://web.archive.org/web/20240914194134/https://www.nhs.uk/conditions/laser-eye-surgery-and-lens-surgery/ |url-status=live }}</ref> Although it is usually temporary, it can develop into chronic and severe [[Keratoconjunctivitis sicca|dry eye syndrome]]. Quality of life can be severely affected by dry-eye syndrome.<ref name="fda-risk">{{cite web |date=8 August 2018 |title=LASIK – What are the risks and how can I find the right doctor for me? |url=https://www.fda.gov/medical-devices/lasik/what-are-risks-and-how-can-i-find-right-doctor-me |access-date=14 September 2024 |publisher=U.S. [[Food and Drug Administration]] (FDA) |archive-date=7 September 2019 |archive-url=https://web.archive.org/web/20190907192304/https://www.fda.gov/medical-devices/lasik/what-are-risks-and-how-can-i-find-right-doctor-me |url-status=dead }}</ref>

Underlying conditions with dry eye such as [[Sjögren's syndrome]] are considered contraindications to Lasik.<ref>{{cite journal |vauthors=Simpson RG, Moshirfar M, Edmonds JN, Christiansen SM, Behunin N |year=2012 |title=Laser in situ keratomileusis in patients with collagen vascular disease: a review of the literature |journal=Clinical Ophthalmology |volume=6 |pages=1827–37 |doi=10.2147/OPTH.S36690 |pmc=3497460 |pmid=23152662 |doi-access=free }}</ref>

Treatments include artificial [[tears]], prescription tears, and punctal occlusion. [[Punctal occlusion]] is accomplished by placing a collagen or silicone plug in the [[tear duct]], which normally drains fluid from the eye. Some patients complain of ongoing dry-eye symptoms despite such treatments and the symptoms may be permanent.<ref name="fda-risk"/>

=== Halos ===
Some post-LASIK patients see halos and starbursts around bright lights at night.<ref name="NYT-20180611" />

Complications due to LASIK have been classified as those that occur due to preoperative, intraoperative, early postoperative, or late postoperative sources:<ref name="Majmudar">Majmudar, PA. [http://www.aao.org/education/focal_points/upload/6202_Mod13.04-2.pdf "LASIK Complications."] ''Focal Points: Clinical Modules for Ophthalmologists.'' American Academy of Ophthalmology. September 2004. {{webarchive|url=https://web.archive.org/web/20060311094336/http://www.aao.org/education/focal_points/upload/6202_Mod13.04-2.pdf|date=11 March 2006}}</ref> According to the UK [[National Health Service]], complications occur in fewer than 5% of cases.<ref name="nhs" />

=== Other complications ===
* Flap complications&nbsp;– The incidence of flap complications is about 0.244%.<ref name="Carrillo">{{cite journal |vauthors=Carrillo C, Chayet AS, Dougherty PJ, Montes M, Magallanes R, Najman J, Fleitman J, Morales A |year=2005 |title=Incidence of complications during flap creation in LASIK using the NIDEK MK-2000 microkeratome in 26,600 cases |journal=Journal of Refractive Surgery |volume=21 |issue=5 Suppl |pages=S655-7 |doi=10.3928/1081-597X-20050902-20 |pmid=16212299}}</ref> Flap complications (such as displaced flaps or folds in the flaps that necessitate repositioning, diffuse lamellar keratitis, and epithelial ingrowth) are common in lamellar corneal surgeries<ref>{{cite web |title=Eye Surgery Education Council |url=https://lasikinstitute.org/Intraoperative.html |url-status=live |archive-url=https://web.archive.org/web/20110928000153/http://www.lasikinstitute.org/Intraoperative.html |archive-date=28 September 2011 |access-date=10 December 2011 |website=Lasikinstitute.org}}</ref> but rarely lead to permanent loss of visual acuity. The incidence of these microkeratome-related complications decreases with increased physician experience.<ref>{{cite journal |vauthors=Tham VM, Maloney RK |date=May 2000 |title=Microkeratome complications of laser in situ keratomileusis |journal=Ophthalmology |volume=107 |issue=5 |pages=920–4 |doi=10.1016/S0161-6420(00)00004-X |pmid=10811084}}</ref>
* Flap interface particles&nbsp;– are a finding whose clinical significance is undetermined.<ref name="Vesaluoma">{{cite journal |vauthors=Vesaluoma M, Pérez-Santonja J, Petroll WM, Linna T, Alió J, Tervo T |date=February 2000 |title=Corneal stromal changes induced by myopic LASIK |url=http://www.iovs.org/cgi/content/full/41/2/369 |journal=Investigative Ophthalmology & Visual Science |volume=41 |issue=2 |pages=369–76 |pmid=10670464 |access-date=25 March 2006 |archive-date=5 September 2010 |archive-url=https://web.archive.org/web/20100905184027/http://www.iovs.org/cgi/content/full/41/2/369 |url-status=live }}</ref> Particles of various sizes and reflectivity are clinically visible in about 38.7% of eyes examined via [[slit lamp]] biomicroscopy and in 100% of eyes examined by [[confocal microscopy]].<ref name="Vesaluoma" />
* [[Diffuse lamellar keratitis]] &nbsp;– an inflammatory process that involves an accumulation of white blood cells at the interface between the LASIK corneal flap and the underlying stroma. It is known colloquially as "sands of Sahara syndrome" because on slit lamp exam, the inflammatory infiltrate appears similar to waves of sand. The USAeyes organisation reports an incidence of 2.3% after LASIK.<ref name="Sun">{{cite journal |vauthors=Sun L, Liu G, Ren Y, Li J, Hao J, Liu X, Zhang Y |year=2005 |title=Efficacy and safety of LASIK in 10,052 eyes of 5081 myopic Chinese patients |journal=Journal of Refractive Surgery |volume=21 |issue=5 Suppl |pages=S633-5 |doi=10.3928/1081-597X-20050902-15 |pmid=16212294}}</ref> It is most commonly treated with steroid eye drops. Sometimes it is necessary for the eye surgeon to lift the flap and manually remove the accumulated cells. DLK has not been reported with photorefractive keratectomy due to the absence of flap creation.
* Infection&nbsp;– the incidence of infection responsive to treatment has been estimated at 0.04%.<ref name="Sun" />
* [[Post-LASIK ectasia|Post-LASIK corneal ectasia]]&nbsp;– a condition where the cornea starts to bulge forwards at a variable time after LASIK, causing irregular astigmatism. the condition is similar to [[keratoconus]].
* Subconjunctival hemorrhage&nbsp;– A report shows the incidence of [[subconjunctival hemorrhage]] has been estimated at 10.5%.<ref name="Sun" /><ref>{{cite web |title=Ectasia After LASIK |url=http://eyewiki.aao.org/Ectasia_After_LASIK |publisher=American Academy of Ophthalmology |access-date=12 June 2013 |archive-date=4 October 2022 |archive-url=https://web.archive.org/web/20221004025657/https://eyewiki.aao.org/Ectasia_After_LASIK |url-status=live }}</ref>
* Corneal scarring&nbsp;– or permanent problems with cornea's shape making it impossible to wear contact lenses.<ref name="HNYT" />
* Epithelial ingrowth&nbsp;– estimated at 0.01%.<ref name="Sun" />
* Traumatic flap dislocations&nbsp;– Cases of late traumatic flap dislocations have been reported up to thirteen years after LASIK.<ref>{{cite journal |vauthors=Galvis V, Tello A, Ortiz AI, Quintero MP, Parra MM, Blanco NA |date=April–June 2019 |title=Traumatic corneal flap avulsion and loss 13 years after LASIK |journal=Saudi Journal of Ophthalmology |volume=33 |issue=2 |pages=172–176 |doi=10.1016/j.sjopt.2018.08.001 |pmc=6664271 |pmid=31384163 |doi-access=free}}</ref>
* [[Retinal detachment]]: estimated at 0.36 percent.<ref name="Ruiz-Moreno">{{cite journal |vauthors=Ruiz-Moreno JM, Alió JL |year=2003 |title=Incidence of retinal disease following refractive surgery in 9,239 eyes |journal=Journal of Refractive Surgery |volume=19 |issue=5 |pages=534–47 |doi=10.3928/1081-597X-20030901-08 |pmid=14518742}}</ref>
* [[Choroidal neovascularization]]: estimated at 0.33 percent.<ref name="Ruiz-Moreno" />
* [[Uveitis]]: estimated at 0.18 percent.<ref name="Suarez">{{cite journal |vauthors=Suarez E, Torres F, Vieira JC, Ramirez E, Arevalo JF |date=October 2002 |title=Anterior uveitis after laser in situ keratomileusis |journal=Journal of Cataract and Refractive Surgery |volume=28 |issue=10 |pages=1793–8 |doi=10.1016/S0886-3350(02)01364-0 |pmid=12388030 |s2cid=11880947}}</ref>
* For climbers&nbsp;– Although the cornea usually is thinner after LASIK, because of the removal of part of the stroma, refractive surgeons strive to maintain the maximum thickness to avoid structurally weakening the cornea. Decreased atmospheric pressure at higher altitudes has not been demonstrated as extremely dangerous to the eyes of LASIK patients. However, some [[mountain climber]]s have experienced a myopic shift at extreme altitudes.<ref>{{cite journal |vauthors=Boes DA, Omura AK, Hennessy MJ |date=December 2001 |title=Effect of high-altitude exposure on myopic laser in situ keratomileusis |journal=Journal of Cataract and Refractive Surgery |volume=27 |issue=12 |pages=1937–41 |doi=10.1016/S0886-3350(01)01074-4 |pmid=11738908 |s2cid=45468164}}</ref><ref>{{cite journal |vauthors=Dimmig JW, Tabin G |year=2003 |title=The ascent of Mount Everest following laser in situ keratomileusis |journal=Journal of Refractive Surgery |volume=19 |issue=1 |pages=48–51 |doi=10.3928/1081-597X-20030101-10 |pmid=12553606}}</ref>
* Late postoperative complications&nbsp;– A large body of evidence on the chances of long-term complications is not yet established and may be changing due to advances in operator experience, instruments and techniques.<ref>{{cite journal |vauthors=Hammer T, Heynemann M, Naumann I, Duncker GI |date=March 2006 |title=[Correction and induction of high-order aberrations after standard and wavefront-guided LASIK and their influence on the postoperative contrast sensitivity] |journal=Klinische Monatsblätter für Augenheilkunde |language=de |volume=223 |issue=3 |pages=217–24 |doi=10.1055/s-2005-858864 |pmid=16552654|s2cid=71611964 }}</ref><ref>{{cite journal |vauthors=Alió JL, Montés-Mico R |date=February 2006 |title=Wavefront-guided versus standard LASIK enhancement for residual refractive errors |journal=Ophthalmology |volume=113 |issue=2 |pages=191–7 |doi=10.1016/j.ophtha.2005.10.004 |pmid=16378639}}</ref><ref>{{cite journal |vauthors=Caster AI, Hoff JL, Ruiz R |year=2005 |title=Conventional vs wavefront-guided LASIK using the LADARVision4000 excimer laser |journal=Journal of Refractive Surgery |volume=21 |issue=6 |pages=S786-91 |doi=10.3928/1081-597X-20051101-28 |pmid=16329381}}</ref><ref name="fda-risk"/>
* Potential best vision loss may occur a year after the surgery regardless of the use of eyewear.<ref>{{Cite web |title=LASIK laser eye surgery |url=http://www.webmd.boots.com/eye-health/guide/lasik-laser-eye-surgery |url-status=dead |archive-url=https://web.archive.org/web/20160515073430/http://www.webmd.boots.com/eye-health/guide/lasik-laser-eye-surgery |archive-date=15 May 2016 |access-date=6 May 2016 |website=Webmd.boots.com }}</ref>
* [[Ocular neuropathic pain]] (corneal neuralgia); rare<ref name="CTV">{{cite news |last1=St. Philip |first1=Elizabeth |last2=Favaro |first2=Avis |date=7 April 2019 |title=Families deal with repercussions after rare but severe complications from laser eye surgery |work=CTV |url=https://www.ctvnews.ca/w5/families-deal-with-repercussions-after-rare-but-severe-complications-from-laser-eye-surgery-1.4363940 |access-date=26 November 2019 |archive-date=14 September 2024 |archive-url=https://web.archive.org/web/20240914194133/https://www.ctvnews.ca/w5/families-deal-with-repercussions-after-rare-but-severe-complications-from-laser-eye-surgery-1.4363940 |url-status=live }}</ref>

=== FDA's position ===
In October 2009, the US FDA, the US [[National Eye Institute]] (NEI), and the US [[Department of Defense]] (DoD) launched the LASIK Quality of Life Collaboration Project (LQOLCP) to help better understand the potential risk of severe problems that can result from LASIK<ref name="FDA1">{{cite web |title=LASIK Quality of Life Collaboration Project |url=https://www.fda.gov/medical-devices/lasik/lasik-quality-life-collaboration-project |access-date=28 November 2014 |publisher=U.S. [[Food and Drug Administration]] (FDA) |archive-date=16 November 2019 |archive-url=https://web.archive.org/web/20191116100221/https://www.fda.gov/medical-devices/lasik/lasik-quality-life-collaboration-project |url-status=dead }}</ref> in response to widespread reports of problems experienced by patients after LASIK laser eye surgery.<ref name="FDA2">{{cite web |date=26 April 2019 |title=The FDA's LASIK Program |url=https://www.fda.gov/medical-devices/lasik/fdas-lasik-program |publisher=U.S. [[Food and Drug Administration]] (FDA) |access-date=14 September 2024 |archive-date=1 July 2024 |archive-url=https://web.archive.org/web/20240701042548/https://www.fda.gov/medical-devices/lasik/fdas-lasik-program |url-status=live }}</ref> This project examined patient-reported outcomes with LASIK (PROWL). The project consisted of three phases: pilot phase, phase I, phase II (PROWL-1) and phase III (PROWL-2).<ref name="FDA3">{{citation |last=Eydelman |first=Malvina B. |title=LASIK Quality of Life Collaboration Project (LQOLCP) |url=https://www.fda.gov/downloads/MedicalDevices/ProductsandMedicalProcedures/SurgeryandLifeSupport/LASIK/UCM419443.pdf |publisher=U.S. [[Food and Drug Administration]] (FDA) |access-date=16 December 2019 |archive-date=24 October 2016 |archive-url=https://web.archive.org/web/20161024002941/http://www.fda.gov/downloads/MedicalDevices/ProductsandMedicalProcedures/SurgeryandLifeSupport/LASIK/UCM419443.pdf |url-status=dead }}</ref>

The results of the LASIK Quality of Life Study were published in October 2014.<ref name="FDA1" />
{{quote frame | text=Based on our initial analyses of our studies:
* Up to 46 percent of participants, who had no visual symptoms before surgery, reported at least one visual symptom at three months after surgery.
* Participants who developed new visual symptoms after surgery, most often developed halos. Up to 40 percent of participants with no halos before LASIK had halos three months following surgery.
* Up to 28 percent of participants with no symptoms of dry eyes before LASIK, reported dry eye symptoms at three months after their surgery.
* Less than 1 percent of study participants experienced "a lot of" difficulty with or inability to do usual activities without corrective lenses because of their visual symptoms (halos, glare, et al.) after LASIK surgery.
* Participants who were not satisfied with the LASIK surgery reported all types of visual symptoms the questionnaire measured (double vision/ghosting, starbursts, glare, and halos).
}}

The FDA's director of the Division of Ophthalmic Devices said about the LASIK study: "Given the large number of patients undergoing LASIK annually, dissatisfaction and disabling symptoms may occur in a significant number of patients".<ref name="FDA3"/> Also in 2014, FDA published an article highlighting the risks and a list of factors and conditions individuals should consider when choosing a doctor for their refractive surgery.<ref name="fda-risk"/>

=== Contraindications ===
Not everyone is eligible to receive LASIK. Severe [[keratoconus]] or thin corneas may disqualify patients from LASIK, though other procedures may be viable options. Those with [[Fuchs' dystrophy|Fuchs' corneal endothelial dystrophy]], corneal epithelial basement membrane dystrophy, [[Retinal detachment|retinal tears]], autoimmune diseases, [[Dry eye syndrome|severe dry eyes]], and significant [[blepharitis]] should be treated before consideration for LASIK. Women who are pregnant or nursing are generally not eligible to undergo LASIK.<ref>{{Cite web |title=LASIK for Myopia and Astigmatism: Safety and Efficacy – EyeWiki |url=https://eyewiki.aao.org/LASIK_for_Myopia_and_Astigmatism:_Safety_and_Efficacy#LASIK_Complications |access-date=6 August 2019 |website=eyewiki.aao.org |archive-date=14 September 2024 |archive-url=https://web.archive.org/web/20240914194642/https://eyewiki.org/LASIK_for_Myopia_and_Astigmatism:_Safety_and_Efficacy#LASIK_Complications |url-status=live }}</ref>

People with large pupils (e.g. due to taking medications or in the younger age group) may be particularly prone to symptoms such as glare, halos, starbursts, and ghost images (double vision) in dim light after surgery. Because the laser can only work on the inner section of the cornea, the outer rim is left unaffected. In dim lighting, a patient's pupils dilate and may be predisposed to optic aberrations due to refractive asynchrony of the two regions with regards to the incoming light.<ref name="FDA L"/>

== Further research ==
{{missing information|section|PresbyLASIK|date=October 2021}}
Since 1991, there have been further developments such as faster lasers; larger spot areas; bladeless flap incisions; intraoperative [[corneal pachymetry]]; and [[wavefront curvature sensor|"wavefront-optimized" and "wavefront-guided"]] techniques which were introduced by the University of Michigan's Center for Ultrafast Optical Science. The goal of replacing standard LASIK in refractive surgery is to avoid permanently weakening the cornea with incisions and to deliver less energy to the surrounding tissues. More recently, techniques like [[Epi-Bowman Keratectomy]] have been developed that avoid touching the epithelial basement membrane or Bowman's layer.<ref>{{Cite web|url=https://www.reviewofophthalmology.com/article/time-to-revisit-surface-ablation|title=Time to Revisit Surface Ablation?|first=Sean|last=McKinney|website=www.reviewofophthalmology.com|access-date=14 August 2020|archive-date=18 October 2021|archive-url=https://web.archive.org/web/20211018082605/https://www.reviewofophthalmology.com/article/time-to-revisit-surface-ablation|url-status=live}}</ref>

=== Experimental techniques ===
* "plain" LASIK: [[LASEK]], [[Epi-LASIK]],
* Wavefront-guided PRK,
* advanced [[intraocular lens]]es.
* [[Femtosecond laser intrastromal vision correction]]: using all-femtosecond correction, for example, [[Femtosecond Lenticule EXtraction]], [[FLIVC]], or IntraCOR),
* Keraflex: a thermobiochemical solution which has received the [[CE marking|CE Mark]] for refractive correction.<ref>{{cite press release|url=http://www.avedro.com/PressReleases/Avedro_CEMark_20April2010.pdf|title=Avedro Receives the European Union's CE Mark for its Vedera Ophthalmic Device|date=20 April 2010|website=Avedro.com|access-date=20 December 2018|archive-date=4 November 2013|archive-url=https://web.archive.org/web/20131104093214/http://www.avedro.com/PressReleases/Avedro_CEMark_20April2010.pdf|url-status=dead}}</ref> and is in European clinical trials for the correction of myopia and keratoconus.<ref>{{cite web |url=http://bmctoday.net/crstodayeurope/2010/05/article.asp?f=industry-interview-aiming-to-change-the-face-of-refractive-surgeryagain |title=CRSTodayEurope.com > May 2010 > Industry interview: Aiming to change the face of refractive surgery—again |website=Bmctoday.net |date=16 April 2010 |access-date=10 December 2011 |archive-date=18 August 2011 |archive-url=https://web.archive.org/web/20110818113109/http://bmctoday.net/crstodayeurope/2010/05/article.asp?f=industry-interview-aiming-to-change-the-face-of-refractive-surgeryagain |url-status=live }}</ref>
* Technolas FEMTEC laser: for incisionless IntraCOR ablation for presbyopia,<ref>{{cite web|url=http://www.2010pv.com/dasat/images/3/100373-luis-ruiz-white-paper-0908-final.pdf|title=IntraCOR for presbyopia|website=2010pv.com|access-date=20 December 2018|archive-url=https://web.archive.org/web/20110902212944/http://www.2010pv.com/dasat/images/3/100373-luis-ruiz-white-paper-0908-final.PDF|archive-date=2 September 2011|url-status=dead}}</ref> with trials ongoing for myopia and other conditions.<ref>{{cite web|url=http://www.2010pv.com/dasat/images/4/100544-1st-tpv-alliance-bali-may-2009.pdf|title=IntraCOR for myopia|website=2010pv.com|access-date=20 December 2018|archive-url=https://web.archive.org/web/20110902213023/http://www.2010pv.com/dasat/images/4/100544-1st-tpv-alliance-bali-may-2009.pdf|archive-date=2 September 2011|url-status=dead}}</ref>
* LASIK with the IntraLase femtosecond laser: early trials comparing to the LASIK with microkeratomes for the correction of myopia suggest no significant differences in safety or efficacy. However, the femtosecond laser has a potential advantage in predictability, although this finding was not significant.<ref>{{cite journal | vauthors = Chen S, Feng Y, Stojanovic A, Jankov MR, Wang Q | title = IntraLase femtosecond laser vs mechanical microkeratomes in LASIK for myopia: a systematic review and meta-analysis | journal = Journal of Refractive Surgery | volume = 28 | issue = 1 | pages = 15–24 | date = January 2012 | pmid = 22233436 | doi = 10.3928/1081597x-20111228-02 | url = http://www.laservalais.ch/wp-content/uploads/Journal-of-Refractive-Surgery-Janvier-2012.pdf | access-date = 1 November 2015 | archive-date = 7 January 2022 | archive-url = https://web.archive.org/web/20220107065657/https://www.laservalais.ch/wp-content/uploads/Journal-of-Refractive-Surgery-Janvier-2012.pdf | url-status = dead }}</ref>

== Comparison to photorefractive keratectomy ==
A systematic review that compared PRK and LASIK concluded that LASIK has shorter recovery time and less pain.<ref name=Shor2013 /> The two techniques after a period of one year have similar results.<ref name=Shor2013>{{cite journal | vauthors = Shortt AJ, Allan BD, Evans JR | title = Laser-assisted in-situ keratomileusis (LASIK) versus photorefractive keratectomy (PRK) for myopia | journal = The Cochrane Database of Systematic Reviews | volume = 1 | issue = 1 | pages = CD005135 | date = January 2013 | pmid = 23440799 | doi = 10.1002/14651858.CD005135.pub3 | pmc = 11848121 }}</ref>

A 2017 systematic review found uncertainty in visual acuity, but found that in one study, those receiving PRK were less likely to achieve a refractive error, and were less likely to have an over-correction compared to LASIK.<ref name="Kuryan">{{cite journal | vauthors = Kuryan J, Cheema A, Chuck RS | title = Laser-assisted subepithelial keratectomy (LASEK) versus laser-assisted in-situ keratomileusis (LASIK) for correcting myopia | journal = The Cochrane Database of Systematic Reviews | volume = 2017 | issue = 2 | pages = CD011080 | date = February 2017 | pmid = 28197998 | pmc = 5408355 | doi = 10.1002/14651858.CD011080.pub2 }}</ref>

== References ==
{{Reflist}}

== External links ==
<!-- PLEASE DO ''not'' ADD LINKS TO COMMERCIAL SITES OR TO SITES THAT ARE ASSOCIATED WITH SPECIFIC PROVIDERS OF LASIK -->
* [https://www.fda.gov/medical-devices/lasik/what-lasik What is LASIK?] – US [[Food and Drug Administration]] (FDA)
* [https://medlineplus.gov/lasereyesurgery.html Laser Eye Surgery] – [[United States National Library of Medicine]]

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[[Category:1989 introductions]]
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