Refractive surgery

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Refractive surgery
US Navy 100217-N-7032B-023 Capt. David J. Tanzer, specialty leader of Navy Refractive Surgery and director of Refractive Surgery Program at Naval Medical Center San Diego, performs a photorefractive keratectomy (PRK) at Naval T.jpg
Surgeon performing a photorefractive keratectomy (PRK)
Specialty ophthalmology, optometry
Types myopia, hyperopia, astigmatism, presbyopia

Refractive surgery is an optional eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea (keratomileusis), lens implantation or lens replacement. The most common methods today use excimer lasers to reshape the curvature of the cornea. Refractive eye surgeries are used to treat common vision disorders such as myopia, hyperopia, presbyopia and astigmatism.

Contents

History

The Excimerlaser that was used for the first LASIK surgeries by Ioannis Pallikaris MEL60-UOC.jpg
The Excimerlaser that was used for the first LASIK surgeries by Ioannis Pallikaris

The first theoretical work on the potential of refractive surgery was published in 1885 by Hjalmar August Schiøtz, an ophthalmologist from Norway. [1] In 1930, the Japanese ophthalmologist Tsutomu Sato made the first attempts at performing this kind of surgery, hoping to correct the vision of military pilots. His approach was to make radial cuts in the cornea, correcting effects by up to 6 diopters. The procedure unfortunately produced a high rate of corneal degeneration, however, and was soon rejected by the medical community.

The first proficient refractive surgery technique was developed in the Barraquer ophthalmologic clinic (Bogotá, Colombia), in 1963, by Jose Barraquer. His technique, called keratomileusis, meaning corneal reshaping (from Greek κέρας (kéras: horn) and σμίλευσις (smileusis: carving)), enabled the correction, not only of myopia, but also of hyperopia. It involves removing a corneal layer, freezing it so that it could be manually sculpted into the required shape, and finally reimplanting the reshaped layer into the eye. In 1980, Swinger performed first keratomileusis surgery in US. [2] In 1985, Krumeich and Swinger introduced non-freeze keratomileusis technique, [2] it remained a relatively imprecise technique.

In 1974 a refractive procedure called Radial Keratotomy (RK) was developed in the USSR by Svyatoslav Fyodorov and later introduced to the United States. RK involves making a number of cuts in the cornea to change its shape and correct refractive errors. The incisions are made with a diamond knife. Following the introduction of RK, doctors routinely corrected nearsightedness, farsightedness, and astigmatism using various applications of incisions on the cornea.

Meanwhile, experiments in 1970 using a xenon dimer and in 1975 using noble gas halides resulted in the invention of a type of laser called an excimer laser. While excimer lasers were initially used for industrial purposes, in 1980, Rangaswamy Srinivasan, a scientist of IBM who was using an excimer laser to make microscopic circuits in microchips for informatics equipment, discovered that the excimer could also be used to cut organic tissues with high accuracy without significant thermal damage. The discovery of an effective biological cutting laser, along with the development of computers to control it, enabled the development of new refractive surgery techniques.

In 1983, Stephen Trokel, a scientist at Columbia University, in collaboration with Theo Seiler and Srinivasan, performed the first Photorefractive Keratectomy (PRK), or keratomileusis in situ (without separation of corneal layer) in Germany. [3] The first patent for this approach, which later became known as LASIK surgery, was granted by the US Patent Office to Gholam Ali. Peyman, MD on June 20, 1989. [4] It involves cutting a flap in the cornea and pulling it back to expose the corneal bed, then using an excimer laser to ablate the exposed surface to the desired shape, and then replacing the flap. The name LASIK was coined in 1991 by University of Crete and the Vardinoyannion Eye. [5]

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 (1983) which claimed the use of UV laser for the ablation of organic tissues.

In 1991, J.T. Lin, Ph.D. (a Chinese Physicist) was granted a US patent [6] for a new technology using a flying-spot for customized LASIK currently used worldwide. The first US patent using an eye-tracking device to prevent decentration in LASIK procedures was granted to another Chinese Physicist, Dr. S. Lai in 1993.

Techniques

Flap procedures

Excimer laser ablation is done under a partial-thickness lamellar corneal flap.

Surface procedures

The excimer laser is used to ablate the most anterior portion of the corneal stroma. These procedures do not require a partial thickness cut into the stroma. Surface ablation methods differ only in the way the epithelial layer is handled.

Corneal incision procedures

Refractive lens exchange

Clear lens extraction or Refractive lens exchange is effectively the same procedure as cataract surgery used to replace a natural lens with high refractive error when other methods are not effective. [13] It can be done in patients with severe refractive error and/or presbyopia who wish to avoid spectacles. [14] [15] In addition to the common complications of cataract surgery, clear lens extraction may also cause premature posterior vitreous detachment and retinal detachment. [14] In some people with very high myopia, the eye may be left aphakic, without intraocular lens implantation. [16]

A related procedure is the implantation of phakic intraocular lenses in series with the natural lens to correct vision in cases of high refractive errors. [17]

Other procedures

Using mid-IR and UV lasers for the treatment of presbyopia by scleral tissue ablation was first proposed and patented by J.T. Lin, Ph.D. in US patents #6,258,082 (in 2001) and #6,824,540 (in 2004).

Expectations

Research conducted by the Magill Research Center for Vision Correction, Medical University of South Carolina, showed that the overall patient satisfaction rate after primary LASIK surgery was 95.4%. They further differentiated between myopic LASIK (95.3%) and hyperopic LASIK (96.3%). They concluded that the vast majority (95.4%) of patients were satisfied with their outcome after LASIK surgery. [20]

Ophthalmologists use various approaches to analyze the results of refractive surgery, and alter their techniques to provide better results in the future. [21] [22] [23] [24] [25] [26] [27] [28] [29] Some of these approaches are programmed into the devices ophthalmologists use to measure the refraction of the eye and the shape of the cornea, such as corneal topography. [30]

Risks

While refractive surgery is becoming more affordable and safe, it may not be recommended for everybody. People with certain eye diseases involving the cornea or retina, pregnant women, and patients who have medical conditions such as glaucoma, diabetes, uncontrolled vascular disease, or autoimmune disease are not good candidates for refractive surgery. Keratoconus, a progressive thinning of the cornea, is a common corneal disorder. Keratoconus occurring after refractive surgery is called Corneal Ectasia. It is believed that additional thinning of the cornea via refractive surgery may contribute to advancement of the disease [31] that may lead to the need for a corneal transplant. Therefore, keratoconus is a contraindication to refractive surgery. Corneal topography and pachymetry are used to screen for abnormal corneas. Furthermore, some people's eye shape may not permit effective refractive surgery without removing excessive amounts of corneal tissue. Those considering laser eye surgery should have a full eye examination.

Although the risk of complications is decreasing compared to the early days of refractive surgery, [32] there is still a small chance for serious problems. These include vision problems such as ghosting, halos, starbursts, double-vision, and dry-eye syndrome. [33] With procedures that create a permanent flap in the cornea (such as LASIK), there is also the possibility of accidental traumatic flap displacement years after the surgery, [34] with potentially disastrous results if not given prompt medical attention. [35]

For patients with strabismus, risks of complications such as diplopia and/or increased strabismus angle need to be evaluated carefully. In case both refractive surgery and strabismus surgery are to be performed, it is recommended that the refractive surgery be done first. [36]

Children

Pediatric refractive surgery involves other risks than refractive surgery on adults, yet it may be indicated especially for children whose cognitive or visual development is failing due to refractive error, [37] in particular in cases of bilateral high refractive error, [38] anisometropia, [39] anisometric amblyopia [38] [40] or accommodative esotropia. [39] [41]

Interventions on young children may require general anaesthesia in order to avoid risks due to involuntary movement, and children have a higher risk of rubbing or manipulating their eyes post-surgically. Changes to refractive error occurring during normal age development need to be accounted for, and children have a higher risk of developing postoperative corneal haze. [42] [43] This risk is particularly relevant with relation to myopic children. [44]

One study evaluated the outcome of LASEK interventions on 53 children aged 10 months to 16 years who had anisometropic amblyopia. The choice of LASEK was made as it was felt it would give fewer complications than LASIK and less post-operative pain than PRK. In the intervention, which was performed under general anaesthesia, the refractive error in the weaker eye was corrected to balance the refractive error of the other eye. Strabismus surgery was performed later if required. After one year, over 60% had improved in best corrected visual acuity (BCVA) in the weaker eye. Notably, over 80% showed stereopsis post-operatively whereas less than 40% had showed stereopsis before. [45]

In addition to corneal refractive procedures (LASIK, PRK and LASEK), intraocular refractive procedures (phakic intraocular lenses, refractive lens exchange and clear lens extraction) are also performed on children. [46]

See also

Related Research Articles

<span class="mw-page-title-main">Farsightedness</span> Eye condition in which light is focused behind instead of on the retina

Far-sightedness, also known as long-sightedness, hypermetropia, and hyperopia, is a condition of the eye where distant objects are seen clearly but near objects appear blurred. This blur is due to incoming light being focused behind, instead of on, the retina due to insufficient accommodation by the lens. Minor hypermetropia in young patients is usually corrected by their accommodation, without any defects in vision. But, due to this accommodative effort for distant vision, people may complain of eye strain during prolonged reading. If the hypermetropia is high, there will be defective vision for both distance and near. People may also experience accommodative dysfunction, binocular dysfunction, amblyopia, and strabismus. Newborns are almost invariably hypermetropic, but it gradually decreases as the newborn gets older.

<span class="mw-page-title-main">LASIK</span> Corrective ophthalmological surgery

LASIK or Lasik, 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. LASIK surgery is performed by an 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.

<span class="mw-page-title-main">Photorefractive keratectomy</span> Refractive eye surgery procedure

Photorefractive keratectomy (PRK) and laser-assisted sub-epithelial keratectomy (LASEK) are laser eye surgery procedures intended to correct a person's vision, reducing dependency on glasses or contact lenses. LASEK and PRK permanently change the shape of the anterior central cornea using an excimer laser to ablate a small amount of tissue from the corneal stroma at the front of the eye, just under the corneal epithelium. The outer layer of the cornea is removed prior to the ablation.

A microkeratome is a precision surgical instrument with an oscillating blade designed for creating the corneal flap in LASIK or ALK surgery. The normal human cornea varies from around 500 to 600 μm in thickness; and in the LASIK procedure, the microkeratome creates an 83 to 200 μm thick flap. The microkeratome uses an oscillating blade system, which has a blade that oscillates horizontally as the blade travels vertically for a precise cut. This piece of equipment is used all around the world to cut the cornea flap. The microkeratome is also used in Descemet's stripping automated endothelial keratoplasty (DSAEK), where it is used to slice a thin layer from the back of the donor cornea, which is then transplanted into the posterior cornea of the recipient. It was invented by Jose Barraquer and Cesar Carlos Carriazo in the 1950s in Colombia.

<span class="mw-page-title-main">Eye surgery</span> Surgery performed on the eye or its adnexa

Eye surgery, also known as ophthalmic surgery or ocular surgery, is surgery performed on the eye or its adnexa. Eye surgery is part of ophthalmology and is performed by an ophthalmologist or eye surgeon. The eye is a fragile organ, and requires due care before, during, and after a surgical procedure to minimize or prevent further damage. An eye surgeon is responsible for selecting the appropriate surgical procedure for the patient, and for taking the necessary safety precautions. Mentions of eye surgery can be found in several ancient texts dating back as early as 1800 BC, with cataract treatment starting in the fifth century BC. It continues to be a widely practiced class of surgery, with various techniques having been developed for treating eye problems.

<span class="mw-page-title-main">Radial keratotomy</span> Refractive surgical procedure to correct myopia (nearsightedness

Radial keratotomy (RK) is a refractive surgical procedure to correct myopia (nearsightedness). It was developed in 1974 by Svyatoslav Fyodorov, a Russian ophthalmologist. It has been largely supplanted by newer, more accurate operations, such as photorefractive keratectomy, LASIK, Epi-LASIK and the phakic intraocular lens.

Keratomileusis, from Greek κέρας and σμίλευσις, or corneal reshaping, is the improvement of the refractive state of the cornea by surgically reshaping it. It is the most common form of refractive surgery. The first usable technique was developed by José Ignacio Barraquer, commonly called "the father of modern refractive surgery."

<span class="mw-page-title-main">Intraocular lens</span> Lens implanted in the eye to treat cataracts or myopia

An intraocular lens (IOL) is a lens implanted in the eye usually as part of a treatment for cataracts or for correcting other vision problems such as short sightedness and long sightedness; a form of refractive surgery. If the natural lens is left in the eye, the IOL is known as phakic, otherwise it is a pseudophakic lens. Both kinds of IOLs are designed to provide the same light-focusing function as the natural crystalline lens. This can be an alternative to LASIK, but LASIK is not an alternative to an IOL for treatment of cataracts.

<span class="mw-page-title-main">Refractive error</span> Problem with focusing light accurately on the retina due to the shape of the eye

Refractive error is a problem with focusing light accurately on the retina due to the shape of the eye and/or cornea. The most common types of refractive error are near-sightedness, far-sightedness, astigmatism, and presbyopia. Near-sightedness results in far away objects being blurry, far-sightedness and presbyopia result in close objects being blurry, and astigmatism causes objects to appear stretched out or blurry. Other symptoms may include double vision, headaches, and eye strain.

<span class="mw-page-title-main">Phakic intraocular lens</span> Lens implanted in eye in addition to the natural lens

A phakic intraocular lens (PIOL) is an intraocular lens that is implanted surgically into the eye to correct refractive errors without removing the natural lens. Intraocular lenses that are implanted into eyes after the eye's natural lens has been removed during cataract surgery are known as pseudophakic.

Automated lamellar keratoplasty (ALK), also known as keratomileusis in situ, is a non-laser lamellar refractive procedure used to correct high degree refractive errors. This procedure can correct large amounts of myopia and hyperopia. However, the resultant change is not as predictable as with other procedures.

ReLExSmall incision lenticule extraction (SMILE), second generation of ReLEx Femtosecond lenticule extraction (FLEx), is a form of laser based refractive eye surgery developed by Carl Zeiss Meditec used to correct myopia, and cure astigmatism. Although similar to LASIK laser surgery, the intrastromal procedure uses a single femtosecond laser referenced to the corneal surface to cleave a thin lenticule from the corneal stroma for manual extraction.

Vision of humans and other organisms depends on several organs such as the lens of the eye, and any vision correcting devices, which use optics to focus the image.

Stephen Updegraff, M.D., FACS is an American refractive surgeon best known for his early involvement in, and contributions to, LASIK. He is a Fellow of the American College of Surgeons, a board-certified member of the American Board of Ophthalmology, a founding member of the American College of Ophthalmic Surgeons, and a member of the International Society of Refractive Surgery, the American Academy of Ophthalmology, the American Society of Cataract and Refractive Surgery, and the Pine Ridge Eye Study Society. Updegraff currently serves as the medical director of Updegraff Vision in St. Petersburg, Florida.

Laser blended vision is a laser eye treatment which is used to treat presbyopia or other age-related eye conditions. It can be used to help people that simply need reading glasses, and also those who have started to need bifocal or varifocal spectacle correction due to ageing changes in the eye. It can be used for people who are also short-sighted (myopia) or long-sighted (hyperopia) and who also may have astigmatism.

The Alpins Method is a system to plan and analyze the results of refractive surgical procedures, such as laser in-situ keratomileus (LASIK). The Alpins Method is also used to plan cataract/toric intraocular lens (IOL) surgical procedures.

SCHWIND eye-tech-solutions GmbH develops, produces and markets devices for the treatment of ametropiae and corneal diseases consisting of laser systems, diagnostic systems, software for individual treatment planning and a microkeratome.

Peter S. Hersh is an American ophthalmologist, researcher, and specialist in LASIK eye surgery, keratoconus, and diseases of the cornea. He co-authored the article in the journal Ophthalmology that presented the results of the study that led to the first approval by the U.S. Food and Drug Administration (FDA) of the excimer laser for the correction of nearsightedness in the United States. Hersh was also medical monitor of the study that led to approval of corneal collagen crosslinking for the treatment of keratoconus. He was the originator, in 2015, of CTAK for keratoconus, patent holder, and co-developer.

Sheraz Daya is a British ophthalmologist. Daya founded the Centre for Sight in 1996, and works in stem-cell research and sight restoration and correction surgery.

Post-LASIK ectasia is a condition similar to keratoconus where the cornea starts to bulge forwards at a variable time after LASIK, PRK, or SMILE corneal laser eye surgery. However, the physiological processes of post-LASIK ectasia seem to be different from keratoconus. The visible changes in the basal epithelial cell and anterior and posterior keratocytes linked with keratoconus were not observed in post-LASIK ectasia.

References

  1. ↑ Schiøtz, H. (1885). "Ein Fall von hochgradigem Hornhautastigmatismus nach Starextraktion: Besserung auf operativem Wege". Arch Augenheilkd. 15: 178–181.
  2. 1 2 Azar, Dimitri T. (2007). "Laser and mechanical microkeratome". Refractive Surgery (2nd ed.). Philadelphia: Mosby / Elsevier. ISBN   978-0-323-03599-6. OCLC   853286620.
  3. ↑ "Theo Seiler". ascrs.org. Retrieved 6 December 2019.
  4. ↑ US Patent #4,840,175, "METHOD FOR MODIFYING CORNEAL CURVATURE"
  5. ↑ "LASIK Eye Surgery". TO VIMA, greek newspaper. 2009-10-11. Retrieved 2017-07-14.
  6. ↑ US Patent #5,520,679
  7. 1 2 Azar, Dimitri T. (2007). "LASIK complications and their management". Refractive Surgery (2nd ed.). Philadelphia: Mosby / Elsevier. ISBN   978-0-323-03599-6. OCLC   853286620.
  8. ↑ Waring, G; Dougherty, PJ; Chayet, A; Fischer, J; Fant, B; Stevens, G; Bains, HS (2007). "Topographically guided LASIK for myopia using the Nidek CXII customized aspheric treatment zone (CATz)". Transactions of the American Ophthalmological Society. 105: 240–6, discussion 247–8. PMC   2258119 . PMID   18427614.
  9. ↑ Li SM, Kang MT, Zhou Y, Wang NL, Lindsley K (2017). "Wavefront excimer laser refractive surgery for adults with refractive errors". Cochrane Database Syst Rev. 6 (6): CD012687. doi:10.1002/14651858.CD012687. PMC   6481747 .
  10. ↑ "LASIK VS LASEK – A Comparison Chart". The-lasik-directory.com. Retrieved 2011-07-05.
  11. ↑ "Refractive Correction With C-TEN" (PDF). Bmctoday.
  12. ↑ "Astigmatic Keratotomy for the Correction of Astigmatism: Background, History of the Procedure, Indications". Medscape . 2023-07-23.
  13. ↑ Moshirfar, Majid; Milner, Dallin; Patel, Bhupendra C. (June 21, 2022). "Cataract Surgery". www.ncbi.nlm.nih.gov. National Center for Biotechnology Information. PMID   32644679 . Retrieved 8 February 2023.
  14. 1 2 "Clear Lens Extraction - EyeWiki". eyewiki.org.
  15. ↑ Michelle, Stephenson. "A Review of Refractive Lens Exchange". Review of Ophthalmology.
  16. ↑ Azar, Dimitri T. (2007). "lenticular and scleralrefractive surgical procedures". Refractive Surgery (2nd ed.). Mosby / Elsevier. p. 13. ISBN   978-0-323-03599-6.
  17. ↑ Barsam, Allon; Allan, Bruce (17 July 2014). "Excimer laser refractive surgery versus phakic intraocular lenses for the correction of moderate to high myopia". Cochrane Database of Systematic Reviews. 2014 (6): CD007679. doi:10.1002/14651858.cd007679.pub4. ISSN   1465-1858. PMC   10726981 . PMID   24937100.
  18. ↑ Christie, B.; Schweigerling, J.; Prince, S.; Silvestrini, T. (2005). "Optical Performance of a Corneal Inlay for Presbyopia". Investigative Ophthalmology & Visual Science. 46 (5): 695. Archived from the original on 2015-01-09.
  19. ↑ Silvestrini, T. A.; Pinsky, P. M.; Christie, B. (2005). "Analysis of Glucose Diffusion Across the Acufocus Corneal Inlay Using a Finite Element Method". Investigative Ophthalmology & Visual Science. 46 (5): 2195. Archived from the original on 2015-01-09.
  20. ↑ Solomon, KD; Fernández De Castro, LE; Sandoval, HP; Biber, JM; Groat, B; Neff, KD; Ying, MS; French, JW; Donnenfeld, ED (2009). "LASIK world literature review: Quality of life and patient satisfaction". Ophthalmology. 116 (4): 691–701. doi:10.1016/j.ophtha.2008.12.037. PMID   19344821.
  21. ↑ Alpins, NA (1993). "A new method of analyzing vectors for changes in astigmatism". Journal of Cataract and Refractive Surgery. 19 (4): 524–33. doi:10.1016/s0886-3350(13)80617-7. PMID   8355160. S2CID   40460505.
  22. ↑ Koch, DD; Kohnen, T; Obstbaum, SA; Rosen, ES (1998). "Format for reporting refractive surgical data". Journal of Cataract and Refractive Surgery. 24 (3): 285–7. doi:10.1016/s0886-3350(98)80305-2. PMID   9559453. S2CID   26740544.
  23. ↑ Alpins, N (2002). "A re-analysis of astigmatism correction". The British Journal of Ophthalmology. 86 (7): 832. doi:10.1136/bjo.86.7.832-a. PMC   1771183 . PMID   12084766.
  24. ↑ Koch, DD (1997). "Excimer laser technology: new options coming to fruition". Journal of Cataract and Refractive Surgery. 23 (10): 1429–30. doi:10.1016/s0886-3350(97)80001-6. PMID   9480341. S2CID   43145363.
  25. ↑ Morlet, N; Minassian, D; Dart, J (2002). "Astigmatism and the analysis of its surgical correction". The British Journal of Ophthalmology. 86 (12): 1458–9. doi:10.1136/bjo.86.12.1458. PMC   1771428 . PMID   12446403.
  26. ↑ Taylor, HR; Carson, CA (1994). "Excimer laser treatment for high and extreme myopia". Transactions of the American Ophthalmological Society. 92: 251–64, discussion 264–70. PMC   1298510 . PMID   7886866.
  27. ↑ Eydelman, MB; Drum, B; Holladay, J; Hilmantel, G; Kezirian, G; Durrie, D; Stulting, RD; Sanders, D; Wong, B (2006). "Standardized analyses of correction of astigmatism by laser systems that reshape the cornea". Journal of Refractive Surgery. 22 (1): 81–95. doi:10.3928/1081-597X-20060101-16. PMID   16447941. S2CID   6400260.
  28. ↑ Koch, DD (2001). "How should we analyze astigmatic data?". Journal of Cataract and Refractive Surgery. 27 (1): 1–3. doi: 10.1016/s0886-3350(00)00826-9 . PMID   11165844.
  29. ↑ Koch, DD (2006). "Astigmatism analysis: the spectrum of approaches". Journal of Cataract and Refractive Surgery. 32 (12): 1977–8. doi: 10.1016/j.jcrs.2006.10.001 . PMID   17137948.
  30. ↑ Ngoei, Enette (February 2013). "Refractive editor's corner of the world: CorT'ing accuracy". EyeWorld. Archived from the original on 3 March 2016. Retrieved 22 April 2013.
  31. ↑ Huang, X; He, X; Tan, X (2002). "Research of corneal ectasia following laser in-situ keratomileusis in rabbits". Yan Ke Xue Bao. 18 (2): 119–22. PMID   15510652.
  32. ↑ "LASIK risks understated". USA Today. June 28, 2001. Retrieved May 22, 2010.
  33. ↑ Haddrill, Marilyn. "LASIK Risks and LASIK Complications". AllAboutVision.com. Retrieved 2011-07-05.
  34. ↑ Srinivasan, M; Prasad, S; Prajna, NV (2004). "Late dislocation of LASIK flap following fingernail injury". Indian Journal of Ophthalmology. 52 (4): 327–8. PMID   15693328.
  35. ↑ Franklin, Quentin J.; Tanzer, David J. (2004). "Late Traumatic Flap Displacement after Laser In Situ Keratomileuisis". Military Medicine. 169 (4): 334–6. doi: 10.7205/milmed.169.4.334 . PMID   15132240.
  36. ↑ Namrata Sharma; Rasik B. Vajpayee; Laurence Sullivan (12 August 2005). "Refractive surgery and strabismus". Step by Step LASIK Surgery. CRC Press. pp. 100–107. ISBN   978-1-84184-469-5.
  37. ↑ Erin D. Stahl: Pediatric refractive surgery, p. 41. In: Mary Lou McGregor (9 August 2014). Pediatric Ophthalmology, An Issue of Pediatric Clinics. Elsevier Health Sciences. pp. 41–47. ISBN   978-0-323-29946-6.
  38. 1 2 Erin D. Stahl: Pediatric refractive surgery, p. 44–46. In: Mary Lou McGregor (9 August 2014). Pediatric Ophthalmology, An Issue of Pediatric Clinics. Elsevier Health Sciences. pp. 41–47. ISBN   978-0-323-29946-6.
  39. 1 2 Ashok Garg; Jorge L Alió (2011). Surgical Techniques in Ophthalmology (Pediatric Ophthalmic Surgery). JP Medical Ltd. pp. 134–138. ISBN   978-93-5025-148-5.
  40. ↑ Kenneth W. Wright, Mehmet Cem Mocan, My experience with pediatric refractive surgery. In: New Orleans Academy of Ophthalmology. Session (2004). At the Crossings: Pediatric Ophthalmology and Strabismus. Kugler Publications. pp. 87–91. ISBN   978-90-6299-198-3.
  41. ↑ Amar Agarwal; Athiya Agarwal; Soosan Jacob (14 May 2009). Refractive Surgery. Jaypee Brothers Publishers. p. 546. ISBN   978-81-8448-412-0.
  42. ↑ Erin D. Stahl: Pediatric refractive surgery, p. 46–47. In: Mary Lou McGregor (9 August 2014). Pediatric Ophthalmology, An Issue of Pediatric Clinics. Elsevier Health Sciences. pp. 41–47. ISBN   978-0-323-29946-6.
  43. ↑ Ashok Garg; Jorge L Alió (2011). Surgical Techniques in Ophthalmology (Pediatric Ophthalmic Surgery). JP Medical Ltd. p. 150. ISBN   978-93-5025-148-5.
  44. ↑ Somayeh Tafaghodi Yousefi; Mohammad Etezad Razavi; Alireza Eslampour (Summer 2014). "Pediatric photorefractive keratectomy for anisometropic amblyopia: A review". Reviews in Clinical Medicine. 1 (4): 212–218. Archived from the original on 2014-10-06. Retrieved 2014-10-05.
  45. ↑ William F. Astle; Jamalia Rahmat; April D. Ingram; Peter T. Huang (December 2007). "Laser-assisted subepithelial keratectomy for anisometropic amblyopia in children: Outcomes at 1 year". Journal of Cataract & Refractive Surgery. 33 (12): 2028–2034. doi:10.1016/j.jcrs.2007.07.024. PMID   18053899. S2CID   1886316.
  46. ↑ Evelyn A. Paysse: Refractive surgery in children, Creig S. Hoyt; David Taylor (30 September 2012). Pediatric Ophthalmology and Strabismus. Elsevier Health Sciences. pp. 714–720. ISBN   978-1-4557-3781-9.
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