Small incision lenticule extraction (SMILE) history, fundamentals of a new refractive surgery technique and clinical outcomes

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• 作者：Dan Z Reinstein ; Timothy J Archer ; Marine Gobbe
• 关键词：Small incision lenticule extraction (SMILE) ; Laser in situ keratomileusis (LASIK) ; Lenticule ; Cap ; Dry eye ; Corneal sensation ; Corneal innervation ; Corneal biomechanics ; Endokeratophakia
• 刊名：Eye and Vision
• 出版年：2014
• 出版时间：December 2014
• 年：2014
• 卷：1
• 期：1
• 全文大小：2464KB
• 参考文献：1.Krueger RR, Juhasz T, Gualano A, Marchi V: The picosecond laser for nonmechanical laser in situ keratomileusis. J Refract Surg 1998, 14:467鈥?69.PubMed
  2.Ito M, Quantock AJ, Malhan S, Schanzlin DJ, Krueger RR: Picosecond laser in situ keratomileusis with a 1053-nm Nd:YLF laser. J Refract Surg 1996, 12:721鈥?28.PubMed
  3.Kurtz RM, Horvath C, Liu HH, Krueger RR, Juhasz T: Lamellar refractive surgery with scanned intrastromal picosecond and femtosecond laser pulses in animal eyes. J Refract Surg 1998, 14:541鈥?48.PubMed
  4.Heisterkamp A, Mamom T, Kermani O, Drommer W, Welling H, Ertmer W, Lubatschowski H: Intrastromal refractive surgery with ultrashort laser pulses: in vivo study on the rabbit eye. Graefes Arch Clin Exp Ophthalmol 2003, 241:511鈥?17.PubMed CrossRef
  5.Ratkay-Traub I, Ferincz IE, Juhasz T, Kurtz RM, Krueger RR: First clinical results with the femtosecond neodynium-glass laser in refractive surgery. J Refract Surg 2003, 19:94鈥?03.PubMed
  6.Reinstein DZ, Archer TJ, Gobbe M, Johnson N: Accuracy and reproducibility of Artemis central flap thickness and visual outcomes of LASIK with the Carl zeiss meditec VisuMax femtosecond laser and MEL 80 excimer laser platforms. J Refract Surg 2010, 26:107鈥?19.PubMed CrossRef
  7.Sekundo W, Kunert K, Russmann C, Gille A, Bissmann W, Stobrawa G, Sticker M, Bischoff M, Blum M: First efficacy and safety study of femtosecond lenticule extraction for the correction of myopia: six-month results. J Cataract Refract Surg 2008, 34:1513鈥?520.PubMed CrossRef
  8.Blum M, Kunert KS, Engelbrecht C, Dawczynski J, Sekundo W: Femtosecond lenticule extraction (FLEx) - Results after 12聽months in myopic astigmatism. Klin Monbl Augenheilkd 2010, 227:961鈥?65.PubMed CrossRef
  9.Vestergaard A, Ivarsen A, Asp S, Hjortdal J脴: Femtosecond (FS) laser vision correction procedure for moderate to high myopia: a prospective study of ReLEx(庐) flex and comparison with a retrospective study of FS-laser in situ keratomileusis. Acta Ophthalmol 2013, 91(4):355-362.PubMed CrossRef
  10.Shah R, Shah S: Effect of scanning patterns on the results of femtosecond laser lenticule extraction refractive surgery. J Cataract Refract Surg 2011, 37:1636鈥?647.PubMed CrossRef
  11.Sekundo W, Kunert KS, Blum M: Small incision corneal refractive surgery using the small incision lenticule extraction (SMILE) procedure for the correction of myopia and myopic astigmatism: results of a 6聽month prospective study. Br J Ophthalmol 2011, 95:335鈥?39.PubMed CrossRef
  12.Shah R, Shah S, Sengupta S: Results of small incision lenticule extraction: All-in-one femtosecond laser refractive surgery. J Cataract Refract Surg 2011, 37:127鈥?37.PubMed CrossRef
  13.Hjortdal JO, Vestergaard AH, Ivarsen A, Ragunathan S, Asp S: Predictors for the outcome of small-incision lenticule extraction for Myopia. J Refract Surg 2012, 28:865鈥?71.PubMed CrossRef
  14.Pande M, Hillman JS: Optical zone centration in keratorefractive surgery. Entrance pupil center, visual axis, coaxially sighted corneal reflex, or geometric corneal center? Ophthalmology 1993, 100:1230鈥?237.PubMed CrossRef
  15.Vetter JM, Holzer MP, Teping C, Weingartner WE, Gericke A, Stoffelns B, Pfeiffer N, Sekundo W: Intraocular pressure during corneal flap preparation: comparison among four femtosecond lasers in porcine eyes. J Refract Surg 2011, 27:427鈥?33.PubMed CrossRef
  16.Vetter JM, Faust M, Gericke A, Pfeiffer N, Weingartner WE, Sekundo W: Intraocular pressure measurements during flap preparation using 2 femtosecond lasers and 1 microkeratome in human donor eyes. J Cataract Refract Surg 2012, 38:2011鈥?018.PubMed CrossRef
  17.Vestergaard A, Ivarsen AR, Asp S, Hjortdal JO: Small-incision lenticule extraction for moderate to high myopia: predictability, safety, and patient satisfaction. J Cataract Refract Surg 2012, 38:2003鈥?010.PubMed CrossRef
  18.Wang Y, Bao XL, Tang X, Zuo T, Geng WL, Jin Y: Clinical study of femtosecond laser corneal small incision lenticule extraction for correction of myopia and myopic astigmatism. Zhonghua Yan Ke Za Zhi 2013, 49:292鈥?98.PubMed
  19.Kamiya K, Shimizu K, Igarashi A, Kobashi H: Visual and refractive outcomes of femtosecond lenticule extraction and small-incision lenticule extraction for myopia. Am J Ophthalmol 2014, 157:128鈥?34. e122.PubMed CrossRef
  20.Sekundo W, Gertnere J, Bertelmann T, Solomatin I: One-year refractive results, contrast sensitivity, high-order aberrations and complications after myopic small-incision lenticule extraction (ReLEx SMILE). Graefes Arch Clin Exp Ophthalmol 2014, 252(5):837-843.PubMed CrossRef
  21.Agca A, Demirok A, Cankaya KI, Yasa D, Demircan A, Yildirim Y, Ozkaya A, Yilmaz OF: Comparison of visual acuity and higher-order aberrations after femtosecond lenticule extraction and small-incision lenticule extraction. Cont Lens Anterior Eye 2014, 37(4):292-296.PubMed CrossRef
  22.Lin F, Xu Y, Yang Y: Comparison of the visual results after SMILE and femtosecond laser-assisted LASIK for myopia. J Refract Surg 2014, 30:248鈥?54.PubMed CrossRef
  23.Ivarsen A, Asp S, Hjortdal J: Safety and complications of more than 1500 small-incision lenticule extraction procedures. Ophthalmology 2014, 121:822鈥?28.PubMed CrossRef
  24.Reinstein DZ, Archer TJ, Gobbe M: Combined corneal topography and corneal wavefront data in the treatment of corneal irregularity and refractive error in LASIK or PRK using the Carl Zeiss Meditec MEL80 and CRS Master. J Refract Surg 2009, 25:503鈥?15.PubMed
  25.Dong Z, Zhou X: Irregular astigmatism after femtosecond laser refractive lenticule extraction. J Cataract Refract Surg 2013, 39:952鈥?54.PubMed CrossRef
  26.Reinstein DZ, Archer TJ, Dickeson ZI, Gobbe M: Trans-epithelial phototherapeutic keratectomy protocol for treating irregular astigmatism based population on epithelial thickness measurements by Artemis very high-frequency digital ultrasound. J Refract Surg 2014, 30:380鈥?87.PubMed CrossRef
  27.Ju WK, Lee JH, Chung TY, Chung ES: Reproducibility of LASIK flap thickness using the zeiss femtosecond laser measured postoperatively by optical coherence tomography. J Refract Surg 2011, 27:106鈥?10.PubMed CrossRef
  28.Ozgurhan EB, Agca A, Bozkurt E, Gencer B, Celik U, Cankaya KI, Demirok A, Yilmaz OF: Accuracy and precision of cap thickness in small incision lenticule extraction. Clin Ophthalmol 2013, 7:923鈥?26.PubMed PubMed Central
  29.Yu ZQ, Xu Y, Yao PJ, Qin B, Zhou XT, Chu RY: Analysis of flap thickness by anterior segment optical coherence tomography in different flap preparation styles of excimer laser surgery. Zhonghua Yan Ke Za Zhi 2010, 46:203鈥?08.PubMed
  30.Yao P, Xu Y, Zhou X: Comparison of the predictability, uniformity and stability of a laser in situ keratomileusis corneal flap created with a VisuMax femtosecond laser or a Moria microkeratome. J Int Med Res 2011, 39:748鈥?58.PubMed CrossRef
  31.Ahn H, Kim JK, Kim CK, Han GH, Seo KY, Kim EK, Kim TI: Comparison of laser in situ keratomileusis flaps created by 3 femtosecond lasers and a microkeratome. J Cataract Refract Surg 2011, 37:349鈥?57.PubMed CrossRef
  32.Issa A, Al Hassany U: Femtosecond laser flap parameters and visual outcomes in laser in situ keratomileusis. J Cataract Refract Surg 2011, 37:665鈥?74.PubMed CrossRef
  33.Reinstein DZ, Archer TJ, Gobbe M: Accuracy and reproducibility of Cap thickness in small incision lenticule extraction. J Refract Surg 2013, 29:810鈥?15.PubMed CrossRef
  34.Zhao J, Yao P, Li M, Chen Z, Shen Y, Zhao Z, Zhou Z, Zhou X: The morphology of corneal cap and its relation to refractive outcomes in femtosecond laser small incision lenticule extraction (SMILE) with anterior segment optical coherence tomography observation. PLoS One 2013, 8:e70208.PubMed CrossRef PubMed Central
  35.Vestergaard AH, Grauslund J, Ivarsen AR, Hjortdal JO: Central corneal sublayer pachymetry and biomechanical properties after refractive femtosecond lenticule extraction. J Refract Surg 2014, 30:102鈥?08.PubMed CrossRef
  36.Tay E, Li X, Chan C, Tan DT, Mehta JS: Refractive lenticule extraction flap and stromal bed morphology assessment with anterior segment optical coherence tomography. J Cataract Refract Surg 2012, 38:1544鈥?551.PubMed CrossRef
  37.Reinstein DZ, Archer TJ, Gobbe M, Silverman RH, Coleman DJ: Repeatability of layered corneal pachymetry with the Artemis very high-frequency digital ultrasound Arc-scanner. J Refract Surg 2010, 26:646鈥?59.PubMed CrossRef
  38.Hall RC, Mohamed FK, Htoon HM, Tan DT, Mehta JS: Laser in situ keratomileusis flap measurements: comparison between observers and between spectral-domain and time-domain anterior segment optical coherence tomography. J Cataract Refract Surg 2011, 37:544鈥?51.PubMed CrossRef
  39.Rosas Salaroli CH, Li Y, Zhang X, Tang M, Branco Ramos JL, Allemann N, Huang D: Repeatability of laser in situ keratomileusis flap thickness measurement by Fourier-domain optical coherence tomography. J Cataract Refract Surg 2011, 37:649鈥?54.PubMed CrossRef
  40.Carl Zeiss M: Visante OCT User鈥檚 manual. In Book Visante OCT User鈥檚 Manual. 2006.
  41.Li Y, Netto MV, Shekhar R, Krueger RR, Huang D: A longitudinal study of LASIK flap and stromal thickness with high-speed optical coherence tomography. Ophthalmology 2007, 114:1124鈥?132.PubMed CrossRef
  42.von Jagow B, Kohnen T: Corneal architecture of femtosecond laser and microkeratome flaps imaged by anterior segment optical coherence tomography. J Cataract Refract Surg 2009, 35:35鈥?1.PubMed CrossRef
  43.Reinstein DZ, Archer TJ, Gobbe M: Lenticule thickness readout for small incision lenticule extraction compared to Artemis three-dimensional very high-frequency digital ultrasound stromal measurements. J Refract Surg 2014, 30:304鈥?09.PubMed CrossRef
  44.Reinstein DZ, Archer TJ, Gobbe M: LASIK flap thickness profile and reproducibility of the standard vs zero compression Hansatome microkeratomes: three-dimensional display with Artemis VHF digital ultrasound. J Refract Surg 2011, 27:417鈥?26.PubMed CrossRef
  45.Reinstein DZ, Archer TJ, Gobbe M, Silverman R, Coleman DJ: Stromal thickness in the normal cornea: three-dimensional display with Artemis very high-frequency digital ultrasound. J Refract Surg 2009, 25:776鈥?86.PubMed CrossRef PubMed Central
  46.Reinstein DZ, Silverman RH, Raevsky T, Simoni GJ, Lloyd HO, Najafi DJ, Rondeau MJ, Coleman DJ: Arc-scanning very high-frequency digital ultrasound for 3D pachymetric mapping of the corneal epithelium and stroma in laser in situ keratomileusis. J Refract Surg 2000, 16:414鈥?30.PubMed
  47.Roberts C: The cornea is not a piece of plastic. J Refract Surg 2000, 16:407鈥?13.PubMed
  48.He J, Bazan NG, Bazan HE: Mapping the entire human corneal nerve architecture. Exp Eye Res 2010, 91:513鈥?23.PubMed CrossRef PubMed Central
  49.Tuisku IS, Lindbohm N, Wilson SE, Tervo TM: Dry eye and corneal sensitivity after high myopic LASIK. J Refract Surg 2007, 23:338鈥?42.PubMed
  50.Wilson SE: Laser in situ keratomileusis-induced (presumed) neurotrophic epitheliopathy. Ophthalmology 2001, 108:1082鈥?087.PubMed CrossRef
  51.Savini G, Barboni P, Zanini M, Tseng SC: Ocular surface changes in laser in situ keratomileusis-induced neurotrophic epitheliopathy. J Refract Surg 2004, 20:803鈥?09.PubMed
  52.Solomon R, Donnenfeld ED, Perry HD: The effects of LASIK on the ocular surface. Ocul Surf 2004, 2:34鈥?4.PubMed CrossRef
  53.Shtein RM: Post-LASIK dry eye. Expert Rev Ophthalmol 2011, 6:575鈥?82.PubMed CrossRef PubMed Central
  54.Reinstein DZ, Archer TJ, Gobbe M, Bartoli E: Corneal sensation after small incision lenticule extraction (SMILE). J Refract Surg 2014, 釁?釁?[In Press].
  55.Wei S, Wang Y: Comparison of corneal sensitivity between FS-LASIK and femtosecond lenticule extraction (ReLEx flex) or small-incision lenticule extraction (ReLEx smile) for myopic eyes. Graefes Arch Clin Exp Ophthalmol 2013, 251(6):1645-1654.PubMed CrossRef
  56.Wei SS, Wang Y, Geng WL, Jin Y, Zuo T, Wang L, Wu D: Early outcomes of corneal sensitivity changes after small incision lenticule extraction and femtosecond lenticule extraction. Zhonghua Yan Ke Za Zhi 2013, 49:299鈥?04.PubMed
  57.Vestergaard AH, Gronbech KT, Grauslund J, Ivarsen AR, Hjortdal JO: Subbasal nerve morphology, corneal sensation, and tear film evaluation after refractive femtosecond laser lenticule extraction. Graefes Arch Clin Exp Ophthalmol 2013, 251:2591鈥?600.PubMed CrossRef
  58.Demirok A, Ozgurhan EB, Agca A, Kara N, Bozkurt E, Cankaya KI, Yilmaz OF: Corneal sensation after corneal refractive surgery with small incision lenticule extraction. Optom Vis Sci 2013, 90:1040鈥?047.PubMed CrossRef
  59.Li M, Zhao J, Shen Y, Li T, He L, Xu H, Yu Y, Zhou X: Comparison of Dry Eye and corneal sensitivity between small incision lenticule extraction and femtosecond LASIK for myopia. PLoS One 2013, 8:e77797.PubMed CrossRef PubMed Central
  60.Li M, Zhou Z, Shen Y, Knorz MC, Gong L, Zhou X: Comparison of corneal sensation between small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK for myopia. J Refract Surg 2014, 30:94鈥?00.PubMed CrossRef
  61.Li M, Niu L, Qin B, Zhou Z, Ni K, Le Q, Xiang J, Wei A, Ma W, Zhou X: Confocal comparison of corneal reinnervation after small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK). PLoS One 2013, 8:e81435.PubMed CrossRef PubMed Central
  62.Mohamed-Noriega K, Riau AK, Lwin NC, Chaurasia SS, Tan DT, Mehta JS: Early corneal nerve damage and recovery following small incision lenticule extraction (SMILE) and laser in situ keratomileusis (LASIK). Invest Ophthalmol Vis Sci 2014, 55:1823鈥?834.PubMed CrossRef
  63.Xu Y, Yang Y: Dry eye after small incision lenticule extraction and LASIK for myopia. J Refract Surg 2014, 30:186鈥?90.PubMed CrossRef
  64.Knox Cartwright NE, Tyrer JR, Jaycock PD, Marshall J: Effects of variation in depth and side Cut angulations in LASIK and thin-flap LASIK using a femtosecond laser: a biomechanical study. J Refract Surg 2012, 28:419鈥?25.PubMed CrossRef
  65.Medeiros FW, Sinha-Roy A, Alves MR, Dupps WJ Jr: Biomechanical corneal changes induced by different flap thickness created by femtosecond laser. Clinics (Sao Paulo) 2011, 66:1067鈥?071.CrossRef
  66.Randleman JB, Dawson DG, Grossniklaus HE, McCarey BE, Edelhauser HF: Depth-dependent cohesive tensile strength in human donor corneas: implications for refractive surgery. J Refract Surg 2008, 24:S85鈥揝89.PubMed
  67.Kohlhaas M, Spoerl E, Schilde T, Unger G, Wittig C, Pillunat LE: Biomechanical evidence of the distribution of cross-links in corneas treated with riboflavin and ultraviolet A light. J Cataract Refract Surg 2006, 32:279鈥?83.PubMed CrossRef
  68.Scarcelli G, Pineda R, Yun SH: Brillouin optical microscopy for corneal biomechanics. Invest Ophthalmol Vis Sci 2012, 53:185鈥?90.PubMed CrossRef PubMed Central
  69.Petsche SJ, Chernyak D, Martiz J, Levenston ME, Pinsky PM: Depth-dependent transverse shear properties of the human corneal stroma. Invest Ophthalmol Vis Sci 2012, 53:873鈥?80.PubMed CrossRef PubMed Central
  70.Winkler M, Shoa G, Xie Y, Petsche SJ, Pinsky PM, Juhasz T, Brown DJ, Jester JV: Three-dimensional distribution of transverse collagen fibers in the anterior human corneal stroma. Invest Ophthalmol Vis Sci 2013, 54:7293鈥?301.PubMed CrossRef
  71.Reinstein DZ, Archer TJ, Randleman JB: Mathematical model to compare the relative tensile strength of the cornea after PRK, LASIK, and small incision lenticule extraction. J Refract Surg 2013, 29:454鈥?60.PubMed CrossRef
  72.Agca A, Ozgurhan EB, Demirok A, Bozkurt E, Celik U, Ozkaya A, Cankaya I, Yilmaz OF: Comparison of corneal hysteresis and corneal resistance factor after small incision lenticule extraction and femtosecond laser-assisted LASIK: a prospective fellow eye study. Cont Lens Anterior Eye 2014, 37:77鈥?0.PubMed CrossRef
  73.Kamiya K, Shimizu K, Igarashi A, Kobashi H, Sato N, Ishii R: Intraindividual comparison of changes in corneal biomechanical parameters after femtosecond lenticule extraction and small-incision lenticule extraction. J Cataract Refract Surg 2014, 40(6):963-970.PubMed CrossRef
  74.Wu D, Wang Y, Zhang L, Wei S, Tang X: Corneal biomechanical effects: Small-incision lenticule extraction versus femtosecond laser-assisted laser in situ keratomileusis. J Cataract Refract Surg 2014, 40(6):954-962.PubMed CrossRef
  75.Reinstein DZ, Gobbe M, Archer TJ: Ocular biomechanics: measurement parameters and terminology. J Refract Surg 2011, 27:396鈥?97.PubMed CrossRef
  76.Goldich Y, Barkana Y, Morad Y, Hartstein M, Avni I, Zadok D: Can we measure corneal biomechanical changes after collagen cross-linking in eyes with keratoconus?鈥揳 pilot study. Cornea 2009, 28:498鈥?02.PubMed CrossRef
  77.Touboul D, Roberts C, Kerautret J, Garra C, Maurice-Tison S, Saubusse E, Colin J: Correlations between corneal hysteresis, intraocular pressure, and corneal central pachymetry. J Cataract Refract Surg 2008, 34:616鈥?22.PubMed CrossRef
  78.Riau AK, Ang HP, Lwin NC, Chaurasia SS, Tan DT, Mehta JS: Comparison of four different VisuMax circle patterns for flap creation after small incision lenticule extraction. J Refract Surg 2013, 29:236鈥?44.PubMed CrossRef
  79.Mohamed-Noriega K, Toh KP, Poh R, Balehosur D, Riau A, Htoon HM, Peh GS, Chaurasia SS, Tan DT, Mehta JS: Cornea lenticule viability and structural integrity after refractive lenticule extraction (ReLEx) and cryopreservation. Mol Vis 2011, 17:3437鈥?449.PubMed PubMed Central
  80.Angunawela RI, Riau AK, Chaurasia SS, Tan DT, Mehta JS: Refractive lenticule re-implantation after myopic ReLEx: a feasibility study of stromal restoration after refractive surgery in a rabbit model. Invest Ophthalmol Vis Sci 2012, 53:4975鈥?985.PubMed CrossRef
  81.Lim CH, Riau AK, Lwin NC, Chaurasia SS, Tan DT, Mehta JS: LASIK following small incision lenticule extraction (SMILE) lenticule re-implantation: a feasibility study of a novel method for treatment of presbyopia. PLoS One 2013, 8:e83046.PubMed CrossRef PubMed Central
  82.Barraquer JI: Queratomileusis y queratofakia. Bogota: Instituto Barraquer de America; 1980.
  83.Barraquer JI: Keratophakia. Trans Ophthalmol Soc U K 1972, 92:499鈥?16.PubMed
  84.Kaufman HE, McDonald MB: Refractive surgery for aphakia and myopia. Trans Ophthalmol Soc U K 1985, 104(Pt 1):43鈥?7.PubMed
  85.Liu H, Zhu W, Jiang AC, Sprecher AJ, Zhou X: Femtosecond laser lenticule transplantation in rabbit cornea: experimental study. J Refract Surg 2012, 28:907鈥?11.PubMed CrossRef
  86.Pradhan KR, Reinstein DZ, Carp GI, Archer TJ, Gobbe M, Gurung R: Femtosecond laser-assisted keyhole endokeratophakia: correction of hyperopia by implantation of an allogeneic lenticule obtained by SMILE from a myopic donor. J Refract Surg 2013, 29:777鈥?82.PubMed CrossRef
  87.Yao P, Zhao J, Li M, Shen Y, Dong Z, Zhou X: Microdistortions in Bowman鈥檚 layer following femtosecond laser small incision lenticule extraction observed by Fourier-domain OCT. J Refract Surg 2013, 29:668鈥?74.PubMed CrossRef
  88.Dong Z, Zhou X, Wu J, Zhang Z, Li T, Zhou Z, Zhang S, Li G: Small incision lenticule extraction (SMILE) and femtosecond laser LASIK: comparison of corneal wound healing and inflammation. Br J Ophthalmol 2014, 98:263鈥?69.PubMed PubMed Central
  89.Agca A, Ozgurhan EB, Yildirim Y, Cankaya KI, Guleryuz NB, Alkin Z, Ozkaya A, Demirok A, Yilmaz OF: Corneal backscatter analysis by in vivo confocal microscopy: fellow eye comparison of small incision lenticule extraction and femtosecond laser-assisted LASIK. J Ophthal 2014, 2014:265012.CrossRef
  
• 作者单位：Dan Z Reinstein (1) (2) (3)
  Timothy J Archer (1)
  Marine Gobbe (1)
  
  1. London Vision Clinic, 138 Harley Street, London, W1G 7LA, UK
  2. Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA
  3. Centre Hospitalier National d鈥橭phtalmologie, Paris, France
  
• 刊物类别：Ophthalmology;
• 刊物主题：Ophthalmology;
• 出版者：BioMed Central
• ISSN：2326-0254

文摘

This review summarizes the current status of the small incision lenticule extraction (SMILE) procedure. Following the early work by Sekundo et al. and Shah et al., SMILE has become increasingly popular. The accuracy of the creation of the lenticule with the VisuMax femtosecond laser (Carl Zeiss Meditec) has been verified using very high-frequency (VHF) digital ultrasound and optical coherence tomography (OCT). Visual and refractive outcomes have been shown to be similar to those achieved with laser in situ keratomileusis (LASIK), notably in a large population reported by Hjortdal, Vestergaard et al. Safety in terms of the change in corrected distance visual acuity (CDVA) has also been shown to be similar to LASIK. It was expected that there would be less postoperative dry eye after SMILE compared to LASIK because the anterior stroma is disturbed only by the small incision, meaning that the anterior corneal nerves should be less affected. A number of studies have demonstrated a lower reduction and faster recovery of corneal sensation after SMILE than LASIK. Some studies have also used confocal microscopy to demonstrate a lower decrease in subbasal nerve fiber density after SMILE than LASIK. The potential biomechanical advantages of SMILE have been modeled by Reinstein et al. based on the non-linearity of tensile strength through the stroma. Studies have reported a similar change in Ocular Response Analyzer (Reichert) parameters after SMILE and LASIK, however, these have previously been shown to be unreliable as a representation of corneal biomechanics. Retreatment options after SMILE are discussed. Tissue addition applications of the SMILE procedure are also discussed including the potential for cryo-preservation of the lenticule for later reimplantation (Mohamed-Noriega, Angunawela, Lim et al.), and a new procedure referred to as endokeratophakia in which a myopic SMILE lenticule is implanted into a hyperopic patient (Pradhan et al.). Finally, studies reporting microdistortions in Bowman鈥檚 layer and corneal wound healing responses are also described. Keywords Small incision lenticule extraction (SMILE) Laser in situ keratomileusis (LASIK) Lenticule Cap Dry eye Corneal sensation Corneal innervation Corneal biomechanics Endokeratophakia