Flap Thickness and the Risk of Complications in Mechanical Microkeratome and Femtosecond Laser In Situ Keratomileusis: A Literature Review and Statistical Analysis

Introduction: A recent Cochrane review found no difference in visual acuity outcomes between femtosecond-assisted laser in situ keratomileusis (LASIK) and LASIK using mechanical microkeratomes (MMKs). This study compares the flap thickness and risk of complications related to flap creation using femtosecond lasers and MMKs. Methods: PubMed and the Web of Science are used to search the medical literature. An extensive search is performed to identify the flap thickness and complications of LASIK as reported up to 15 July 2021. The following keywords are used in various combinations: Corneal flap, femtosecond laser, laser in situ keratomileusis, laser-assisted in situ keratomileusis, LASIK, mechanical microkeratome. Results: After removing duplicates and irrelevant studies, 122 articles were included for review. Pooled differences for intended vs. postoperative flap thickness using MMKs and femtosecond laser were −4.07 μm (95% CI: −19.55, 3.24 μm) in studies on the MMK and 5.43 μm (95% CI: 2.30, 7.84 μm; p < 0.001), respectively. After removing the studies evaluating outcomes of the old generation Hansatome MMKs (which had a significantly greater variation of flap thickness), the pooled difference for newer MMKs was 4.97 μm (95% CI: 0.35, 9.58 μm; p < 0.001), but the results still favored the femtosecond laser. Uncommon and mild complications unique for the femtosecond LASIK are epithelial gas breakthrough, opaque bubble layer, transient light sensitivity syndrome, and rainbow glare. A single study reported a very low, but stastically different risk of postoperative flap slippage (0.033% for MMK LASIK, and 0.003% for femtosecond LASIK, respectively). Conclusion: In both manual microkeratome and femtosecond LASIK, intra- and postoperative complications were uncommon. The evidence of the superiority of one technique in terms of complications over another cannot be indisputably stated.

[1]  Xiaogang Wang,et al.  Current Developments in Corneal Topography and Tomography , 2021, Diagnostics.

[2]  F. Noorizadeh,et al.  Keratorefractive Surgery Outcomes in Keratoconus Suspect Patients , 2020, Journal of Ophthalmology.

[3]  J. Alió,et al.  The benefits and drawbacks of femtosecond laser-assisted cataract surgery , 2020, European journal of ophthalmology.

[4]  C. Castillo-Salgado,et al.  Laser-assisted in-situ keratomileusis (LASIK) with a mechanical microkeratome compared to LASIK with a femtosecond laser for LASIK in adults with myopia or myopic astigmatism. , 2020, The Cochrane database of systematic reviews.

[5]  M. Teus,et al.  Evolution of visual acuity, flap thickness, and optical density after laser in situ keratomileusis performed with a femtosecond laser. , 2020, Journal of cataract and refractive surgery.

[6]  A. Grzybowski,et al.  Does Corneal Refractive Surgery Increase the Risk of Retinal Detachment? A Literature Review and Statistical Analysis. , 2019, Journal of refractive surgery.

[7]  M. Nassr,et al.  Comparison of Laser In Situ Keratomileusis Flap Morphology and Predictability by WaveLight FS200 Femtosecond Laser and Moria Microkeratome: An Anterior Segment Optical Coherence Tomography Study , 2019, Korean journal of ophthalmology : KJO.

[8]  A. Grzybowski,et al.  Early postoperative intraocular pressure elevation following cataract surgery , 2019, Current opinion in ophthalmology.

[9]  M. Moshirfar,et al.  Comparative Analysis of LASIK Flap Diameter and its Centration Using Two Different Femtosecond Lasers , 2019, Medical hypothesis, discovery & innovation ophthalmology journal.

[10]  J. Mehta,et al.  Eighteen-year prospective audit of LASIK outcomes for myopia in 53 731 eyes , 2018, British Journal of Ophthalmology.

[11]  R. Krueger,et al.  A review of small incision lenticule extraction complications , 2018, Current opinion in ophthalmology.

[12]  Yu Zhang,et al.  High incidence of rainbow glare after femtosecond laser assisted-LASIK using the upgraded FS200 femtosecond laser , 2018, BMC Ophthalmology.

[13]  Vivek Singh,et al.  Cellular Therapy With Human Autologous Adipose-Derived Adult Stem Cells for Advanced Keratoconus. , 2017, Cornea.

[14]  Eman A. Awad,et al.  Visumax femtolasik versus Moria M2 microkeratome in mild to moderate myopia: efficacy, safety, predictability, aberrometric changes and flap thickness predictability , 2017, BMC Ophthalmology.

[15]  S. Melki,et al.  Risk Factors for Retreatment Following Myopic LASIK with Femtosecond Laser and Custom Ablation for the Treatment of Myopia , 2017, Seminars in ophthalmology.

[16]  O. Muftuoglu,et al.  Corneal flap thickness with the Moria M2 single-use head 90 microkeratome in 72 consecutive LASIK procedures , 2017, Clinical ophthalmology.

[17]  R. Khoramnia,et al.  [Influence of Different Ablation Frequencies on the Clinical Results of Photorefractive Keratectomy Using the Same Excimer Laser Platform: A Contralateral Eye Study]. , 2016, Klinische Monatsblatter fur Augenheilkunde.

[18]  M. Moshirfar,et al.  Rainbow glare after laser-assisted in situ keratomileusis: a review of literature , 2016, Clinical ophthalmology.

[19]  R. Pokroy,et al.  Myopic laser in situ keratomileusis retreatment: Incidence and associations , 2016, Journal of cataract and refractive surgery.

[20]  Yuehua Zhou,et al.  Comparison of corneal flaps created by Wavelight FS200 and Intralase FS60 femtosecond lasers. , 2016, International journal of ophthalmology.

[21]  M. Elfayoumi,et al.  Moria One-Use Plus sub-Bowman’s keratomileusis head: a useful tool in the refractive surgeon’s armamentarium , 2016 .

[22]  P. Versace,et al.  Small incision lenticule extraction (SMILE) in 2015 , 2016, Clinical & experimental optometry.

[23]  G. Auffarth,et al.  Einfluss unterschiedlicher Ablationsfrequenzen auf die klinischen Ergebnisse bei photorefraktiver Keratektomie unter Verwendung derselben Excimer-Laser-Plattform: Ein kontralateraler Vergleich , 2016, Klinische Monatsblätter für Augenheilkunde.

[24]  S. Bechara,et al.  Ectasia risk factors in refractive surgery , 2016, Clinical ophthalmology.

[25]  M. Netto,et al.  Femtosecond Laser-Assisted LASIK Flap Complications. , 2016, Journal of refractive surgery.

[26]  K. Stonecipher,et al.  Laser in situ keratomileusis flap complications and complication rates using mechanical microkeratomes versus femtosecond laser: Retrospective review , 2015 .

[27]  D. Gatinel,et al.  Opaque Bubble Layer Risk Factors in Femtosecond Laser-assisted LASIK. , 2015, Journal of refractive surgery.

[28]  C. McAlinden,et al.  The evolution of corneal and refractive surgery with the femtosecond laser , 2015, Eye and Vision.

[29]  D. Gatinel,et al.  Simultaneous Correction of Unilateral Rainbow Glare and Residual Astigmatism by Undersurface Flap Photoablation After Femtosecond Laser-Assisted LASIK. , 2015, Journal of refractive surgery.

[30]  David Huang,et al.  Corneal Epithelial Remodeling after LASIK Measured by Fourier-Domain Optical Coherence Tomography , 2015, Journal of ophthalmology.

[31]  M. Torres.  Small Incision Lenticule Extraction (SMILE) , 2015 .

[32]  Yuehua Zhou,et al.  Comparison of Laser In Situ Keratomileusis Flaps Created by 2 Femtosecond Lasers , 2015, Cornea.

[33]  J. Alió,et al.  Vertical Gas Breakthrough During Femtosecond Laser Flap Creation for Laser In Situ Keratomileusis in an Eye with Previous Microkeratome Flap , 2015 .

[34]  J. Salz.  Suction Break After Complete Raster Pattern and Incomplete Side Cut , 2015 .

[35]  S. Melki.  Intraoperative Complications: Free Cap in Femtosecond LASIK , 2015 .

[36]  D. Azar,et al.  Difficult and Complicated Cases in Refractive Surgery , 2015 .

[37]  E. A. Razgulyaeva.  Rescue of Primary Incomplete Microkeratome Flap with Secondary Femtosecond Laser Flap in LASIK , 2014, Case reports in ophthalmological medicine.

[38]  R. Krueger,et al.  Management of bilateral gas-bubble breakthrough during femtosecond LASIK in the presence of anterior basement membrane dystrophy. , 2014, Journal of cataract and refractive surgery.

[39]  R. Khoramnia,et al.  Intrastromal femtosecond laser surgical compensation of presbyopia with six intrastromal ring cuts: 3-year results , 2014, British Journal of Ophthalmology.

[40]  G. Waring,et al.  Microkeratome versus femtosecond flaps: accuracy and complications , 2014, Current opinion in ophthalmology.

[41]  J. Mehta,et al.  Comparative study of nJ- and μJ-energy level femtosecond lasers: evaluation of flap adhesion strength, stromal bed quality, and tissue responses. , 2014, Investigative ophthalmology & visual science.

[42]  Jing Zhang,et al.  Comparison of corneal flap thickness using a FS200 femtosecond laser and a moria SBK microkeratome. , 2014, International journal of ophthalmology.

[43]  Chun-Hsiu Liu,et al.  Opaque bubble layer: Incidence, risk factors, and clinical relevance , 2014, Journal of cataract and refractive surgery.

[44]  Erik M Ostler,et al.  Rate of ectasia and incidence of irregular topography in patients with unidentified preoperative risk factors undergoing femtosecond laser-assisted LASIK , 2013, Clinical ophthalmology.

[45]  S. Panagopoulou,et al.  Comparative study of stromal bed of LASIK flaps created with femtosecond lasers (IntraLase FS150, WaveLight FS200) and mechanical microkeratome , 2013, British Journal of Ophthalmology.

[46]  M. Tomita,et al.  Comparison of DLK incidence after laser in situ keratomileusis associated with two femtosecond lasers: Femto LDV and IntraLase FS60 , 2013, Clinical ophthalmology.

[47]  D. Gatinel,et al.  Unilateral rainbow glare after uncomplicated femto-LASIK using the FS-200 femtosecond laser. , 2013, Journal of refractive surgery.

[48]  Yu Zhang,et al.  Comparison of corneal flap morphology using AS-OCT in LASIK with the WaveLight FS200 femtosecond laser versus a mechanical microkeratome. , 2013, Journal of refractive surgery.

[49]  P. Majmudar,et al.  Femtosecond lasers for LASIK flap creation: a report by the American Academy of Ophthalmology. , 2013, Ophthalmology.

[50]  R. Khoramnia,et al.  [Functional results after bilateral intrastromal femtosecond laser correction of presbyopia]. , 2013, Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft.

[51]  H. K. Soong,et al.  Anterior chamber gas bubbles during femtosecond laser flap creation in LASIK: video evidence of entry via trabecular meshwork. , 2012, Journal of cataract and refractive surgery.

[52]  Christof Donitzky,et al.  Safety, efficacy, predictability and stability of laser in situ keratomileusis (LASIK) with a 1000‐Hz scanning spot excimer laser , 2012, Acta ophthalmologica.

[53]  Roni M. Shtein,et al.  Diffuse lamellar keratitis after laser in situ keratomileusis with femtosecond laser flap creation , 2012, Journal of cataract and refractive surgery.

[54]  K. Kobuch,et al.  Precision, Morphology, and Histology of Corneal Flap Cuts Using a 200-kHz Femtosecond Laser , 2012, European journal of ophthalmology.

[55]  Mark Tomalla,et al.  Intrastromal femtosecond laser presbyopia correction: 1-year results of a multicenter study. , 2012, Journal of refractive surgery.

[56]  Z. Nagy,et al.  The role of femtolaser in cataract surgery. , 2012, Klinika oczna.

[57]  M. Jankov,et al.  IntraLase femtosecond laser vs mechanical microkeratomes in LASIK for myopia: a systematic review and meta-analysis. , 2012, Journal of refractive surgery.

[58]  C. Baudouin,et al.  [Corneal imaging]. , 2012, Journal francais d'ophtalmologie.

[59]  N. Nakamura,et al.  Management and outcomes of suction loss during LASIK flap creation with a femtosecond laser. , 2012, Journal of refractive surgery.

[60]  C. Donitzky,et al.  First clinical results with a new 200 kHz femtosecond laser system , 2011, British Journal of Ophthalmology.

[61]  Sanjay V. Patel,et al.  Femtosecond laser versus mechanical microkeratome laser in situ keratomileusis for myopia: Metaanalysis of randomized controlled trials , 2011, Journal of cataract and refractive surgery.

[62]  G. Clare,et al.  Early flap displacement after LASIK. , 2011, Ophthalmology.

[63]  S. Al-Obeidan,et al.  Intraoperative flap complications in laser in situ keratomileusis with two types of microkeratomes. , 2011, Saudi journal of ophthalmology : official journal of the Saudi Ophthalmological Society.

[64]  I. Hamade,et al.  Late onset corneal ectasia after LASIK surgery. , 2011, Saudi journal of ophthalmology : official journal of the Saudi Ophthalmological Society.

[65]  P. Yao,et al.  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 , 2011, The Journal of international medical research.

[66]  A. Mostafaie,et al.  Femtosecond Laser Versus Mechanical Microkeratome in Thin-Flap Laser in Situ Keratomileusis (Lasik) for Correction of Refractive Errors an Evidence-Based Effectiveness and Cost Analysis , 2011 .

[67]  E. K. Kim,et al.  Comparison of laser in situ keratomileusis flaps created by 3 femtosecond lasers and a microkeratome , 2011, Journal of cataract and refractive surgery.

[68]  Ji Hye Song,et al.  Factors Influencing Corneal Flap Thickness in Laser In Situ Keratomileusis with a Femtosecond Laser , 2011, Korean journal of ophthalmology : KJO.

[69]  M. Moshirfar,et al.  Laser in situ keratomileusis flap complications using mechanical microkeratome versus femtosecond laser: Retrospective comparison , 2010, Journal of cataract and refractive surgery.

[70]  C. Lohmann,et al.  Corneal collagen crosslinking in post-LASIK keratectasia , 2010, British Journal of Ophthalmology.

[71]  J. Mehta,et al.  A 10-year prospective audit of LASIK outcomes for myopia in 37,932 eyes at a single institution in Asia. , 2010, Ophthalmology.

[72]  Ming Wang,et al.  Safety and effectiveness of thin-flap LASIK using a femtosecond laser and microkeratome in the correction of high myopia in Chinese patients. , 2010, Journal of refractive surgery.

[73]  C. Rapuano.  A Prospective, Contralateral Eye Study Comparing Thin-Flap LASIK (Sub-Bowman Keratomileusis) with Photorefractive Keratectomy , 2010 .

[74]  W. Culbertson,et al.  Complications of LASIK flaps made by the IntraLase 15- and 30-kHz femtosecond lasers. , 2009, Journal of refractive surgery.

[75]  Marcella Q. Salomão,et al.  Dry eye associated with laser in situ keratomileusis: Mechanical microkeratome versus femtosecond laser , 2009, Journal of cataract and refractive surgery.

[76]  Samuel H. Chung,et al.  Surgical applications of femtosecond lasers , 2009, Journal of biophotonics.

[77]  S. Schallhorn,et al.  Femtosecond laser versus mechanical microkeratome: a retrospective comparison of visual outcomes at 3 months. , 2009, Journal of refractive surgery.

[78]  R. Krueger,et al.  Incidence of rainbow glare after laser in situ keratomileusis flap creation with a 60 kHz femtosecond laser , 2009, Journal of cataract and refractive surgery.

[79]  Stephen G Slade,et al.  A prospective, contralateral eye study comparing thin-flap LASIK (sub-Bowman keratomileusis) with photorefractive keratectomy. , 2009, Ophthalmology.

[80]  C. Lobo,et al.  Femtosecond laser versus mechanical microkeratomes for flap creation in laser in situ keratomileusis and effect of postoperative measurement interval on estimated femtosecond flap thickness , 2009, Journal of cataract and refractive surgery.

[81]  C. Lohmann,et al.  [Cut quality of a new femtosecond laser system]. , 2009, Klinische Monatsblatter fur Augenheilkunde.

[82]  M. O'Keefe,et al.  Prophylaxis of diffuse lamellar keratitis with intraoperative interface steroids in LASIK. , 2009, Journal of refractive surgery.

[83]  R. D. Stulting,et al.  Incidence, outcomes, and risk factors for retreatment after wavefront-optimized ablations with PRK and LASIK. , 2009, Journal of refractive surgery.

[84]  T. Kohnen,et al.  Corneal architecture of femtosecond laser and microkeratome flaps imaged by anterior segment optical coherence tomography , 2009, Journal of cataract and refractive surgery.

[85]  C. A. Utine,et al.  Visante® anterior segment OCT in a patient with gas bubbles in the anterior chamber after femtosecond laser corneal flap formation , 2010, International Ophthalmology.

[86]  Rex D. Hamilton,et al.  Differences in the corneal biomechanical effects of surface ablation compared with laser in situ keratomileusis using a microkeratome or femtosecond laser , 2008, Journal of cataract and refractive surgery.

[87]  J. Ou,et al.  Comparison of the femtosecond laser and mechanical keratome for laser in situ keratomileusis. , 2008, Archives of ophthalmology.

[88]  Urs Vossmerbaeumer,et al.  Comparison of flap adhesion strength using the Amadeus microkeratome and the IntraLase iFS femtosecond laser in rabbits. , 2008, Journal of refractive surgery.

[89]  Chris Hodge,et al.  Accuracy and precision of LASIK flap thickness using the IntraLase femtosecond laser in 1000 consecutive cases. , 2008, Journal of refractive surgery.

[90]  Michael I. Seider,et al.  Epithelial breakthrough during IntraLase flap creation for laser in situ keratomileusis. , 2008, Journal of cataract and refractive surgery.

[91]  I. Bahar,et al.  Incidence, possible risk factors, and potential effects of an opaque bubble layer created by a femtosecond laser , 2008, Journal of cataract and refractive surgery.

[92]  Zsolt Bor,et al.  Rainbow glare as an optical side effect of IntraLASIK. , 2008, Ophthalmology.

[93]  J. Alió,et al.  Very high-frequency digital ultrasound measurement of the LASIK flap thickness profile using the IntraLase femtosecond laser and M2 and Carriazo-Pendular microkeratomes. , 2008, Journal of refractive surgery.

[94]  S. Srinivasan,et al.  Sub-epithelial gas breakthrough during femtosecond laser flap creation for LASIK , 2007, British Journal of Ophthalmology.

[95]  Sanjay V. Patel,et al.  Femtosecond laser versus mechanical microkeratome for LASIK: a randomized controlled study. , 2007, Ophthalmology.

[96]  J. Beltrán,et al.  Effect of preoperative keratometric power on intraoperative complications in LASIK in 34,099 eyes. , 2007, Journal of refractive surgery.

[97]  D. B. Tran,et al.  Comparative Study of Stromal Bed Quality by Using Mechanical, IntraLase Femtosecond Laser 15- and 30-kHz Microkeratomes , 2007, Cornea.

[98]  D. B. Tran,et al.  A 60 kHz IntraLase femtosecond laser creates a smoother LASIK stromal bed surface compared to a Zyoptix XP mechanical microkeratome in human donor eyes. , 2007, Journal of refractive surgery.

[99]  H. Uusitalo,et al.  Corneal flap thickness with the Moria M2 single-use head 90 microkeratome. , 2006, Acta ophthalmologica Scandinavica.

[100]  J. Alió,et al.  Confocal microscopy comparison of intralase femtosecond laser and Moria M2 microkeratome in LASIK. , 2006, Journal of refractive surgery.

[101]  J. L. Hernández-Verdejo,et al.  Porcine model to compare real-time intraocular pressure during LASIK with a mechanical microkeratome and femtosecond laser. , 2007, Investigative ophthalmology & visual science.

[102]  M. Mrochen,et al.  [Femtosecond laser for refractive corneal surgery: foundations, mode of action and clinical applications]. , 2006, Der Ophthalmologe : Zeitschrift der Deutschen Ophthalmologischen Gesellschaft.

[103]  J. Alió,et al.  Transient light‐sensitivity syndrome after laser in situ keratomileusis with the femtosecond laser: Incidence and prevention , 2006, Journal of cataract and refractive surgery.

[104]  Mike P Holzer,et al.  Femtosecond laser-assisted corneal flap cuts: morphology, accuracy, and histopathology. , 2006, Investigative ophthalmology & visual science.

[105]  J. Talamo,et al.  Reproducibility of flap thickness with IntraLase FS and Moria LSK-1 and M2 microkeratomes. , 2006, Journal of refractive surgery.

[106]  Hyun-jeung Choi,et al.  A femtosecond laser creates a stronger flap than a mechanical microkeratome. , 2006, Investigative ophthalmology & visual science.

[107]  P. Binder,et al.  Transient light sensitivity after femtosecond laser flap creation: Clinical findings and management , 2006, Journal of cataract and refractive surgery.

[108]  H. Eleftheriadis,et al.  The effect of flap thickness on the visual and refractive outcome of myopic laser in situ keratomileusis , 2005, Eye.

[109]  P. Dougherty,et al.  Incidence of complications during flap creation in LASIK using the NIDEK MK-2000 microkeratome in 26,600 cases. , 2005, Journal of refractive surgery.

[110]  R. Duffey,et al.  Thin flap laser in situ keratomileusis: Flap dimensions with the Moria LSK‐One manual microkeratome using the 100‐μm head , 2005, Journal of cataract and refractive surgery.

[111]  J. Pepose,et al.  Factors predictive of LASIK flap thickness with the Hansatome zero compression microkeratome. , 2005, Journal of refractive surgery.

[112]  Marivaldo Oliveira,et al.  Intraoperative microkeratome complications in 47,094 laser in situ keratomileusis surgeries. , 2004, Journal of refractive surgery.

[113]  Guy M Kezirian,et al.  Comparison of the IntraLase femtosecond laser and mechanical keratomes for laser in situ keratomileusis , 2004, Journal of cataract and refractive surgery.

[114]  Perry S Binder,et al.  Flap dimensions created with the IntraLase FS laser , 2004, Journal of cataract and refractive surgery.

[115]  C. Joo,et al.  Clinical results of laser in situ keratomileusis with superior and nasal hinges. , 2003, Journal of cataract and refractive surgery.

[116]  K. Fry,et al.  Incidence and associations of retreatment after LASIK. , 2003, Ophthalmology.

[117]  Raj Shekhar,et al.  Mathematical model of corneal surface smoothing after laser refractive surgery. , 2003, American journal of ophthalmology.

[118]  M. Taravella,et al.  Incidence of intraoperative flap complications in laser in situ keratomileusis , 2002, Journal of cataract and refractive surgery.

[119]  N. Çağıl,et al.  Outcome of flap subluxation after laser in situ keratomileusis: results of 6 month follow-up. , 2000, Journal of cataract and refractive surgery.

[120]  R. Maloney,et al.  Microkeratome complications of laser in situ keratomileusis. , 2000, Ophthalmology.

[121]  R. D. Stulting,et al.  Complications of laser in situ keratomileusis for the correction of myopia. , 2000, Ophthalmology.

[122]  D. Fan,et al.  Management of severe flap wrinkling or dislodgment after laser in situ keratomileusis. , 1999, Journal of cataract and refractive surgery.

[123]  R. Maloney,et al.  Flap complications associated with lamellar refractive surgery. , 1999, American journal of ophthalmology.