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LASIK is safe in the long run; looking back at 50 years of lamellar corneal surgery Dan Z Reinstein MD MA(Cantab) FRCSC FR...
What do we know about the long-term safety of LASIK?
National Institute for Clinical Excellence – UK “ guidance on the use of new and existing medicines, treatments and proced...
NICE Report – Long-term Safety – December 2004 <ul><li>“ 1.2 There are concerns about the procedure’s safety in the long-t...
Why did NICE come to this conclusion? <ul><li>Over 17 million procedures worldwide by the end of 2004 </li></ul><ul><li>Ab...
Published Long-Term  PRK  Outcomes -  Myopia Stability Safety 136 eyes Mean SE: -11.40 D Summit Technology UV 200 Optical ...
Published Long-Term  LASIK  Outcomes -  Myopia Stability Safety 33 eyes Mean SE: -11.40 D Schwind Keratom I Chiron ALK 130...
Published Long-Term  LASIK  Outcomes -  Hyperopia 125 eyes Mean SE: +3.84 D Chiron Technolas Keracor 117C Chiron Corneal S...
Media Response to the NICE Report
NICE Request a Systematic Review
What  else  do we know about the long-term safety of LASIK? History of LASIK: Keratomileusis
Jose Barraquer: Keratomileusis <ul><li>Jose Barraquer invented a new innovative method of vision correction: Keratomileusi...
Jose Barraquer: Keratomileusis <ul><li>Cut and freeze a ~300  µm  corneal disc </li></ul>
Jose Barraquer: Keratomileusis <ul><li>Reshape the corneal disc to reduce myopia – shape change calculated using trigonome...
Jose Barraquer: Keratomileusis <ul><li>Reshaping achieved using a lathe </li></ul>
Jose Barraquer: Keratomileusis <ul><li>The corneal disc is sutured back onto the eye </li></ul>
Jose Barraquer: Keratomileusis
Jose Barraquer: Predicting & Shaping the Future <ul><li>Barraquer invented or described nearly all the instruments and tec...
Keratomileusis: 21-Year Outcomes <ul><li>2,686 myopic eyes treated between 1970 and 1990 </li></ul><ul><li>86.1% of patien...
Keratomileusis: 21-Year Outcomes <ul><li>Analysis performed on 1,606 eyes that were not reoperated </li></ul><ul><li>60% o...
Keratomileusis: Ectasia <ul><li>45 cases of ectasia out of 1,606 eyes (2.80%) </li></ul><ul><li>Barraquer found ectasia in...
Keratomileusis Early Cohort vs Modern LASIK Keratomileusis LASIK Range of myopia Up to -27.00 D 86% above -7.01 D Rarely t...
Keratomileusis Early Cohort vs Modern LASIK Keratomileusis LASIK Range of myopia Up to -27.00 D 86% above -7.01 D Rarely t...
What  else  do we know about the long-term safety of LASIK? Screening for Keratoconus
Topography Screening for Keratoconus
Pentacam Screening for Keratoconus
Ocular Response Analyzer <ul><li>Measurement of the stiffness of the cornea </li></ul><ul><li>Could help diagnose keratoco...
Genetic Testing <ul><li>Aquaporin 5 (AQP5) = important water channel protein </li></ul><ul><li>Absence of AQP5 transcripts...
LASIK / PRK in Keratoconus / Forme Fruste KC? ? Diagnosis LASIK PRK Normal Keratoconus Forme Fruste Keratoconus
Can you do PRK in Forme Fruste Keratoconus? <ul><li>Case reports of ectasia following PRK in FFKC </li></ul><ul><ul><li>Le...
Is Forme Fruste Keratoconus a Diagnosis? <ul><li>No! </li></ul><ul><li>Means: “looks like keratoconus” </li></ul><ul><li>P...
PURPOSE <ul><li>To use epithelial thickness mapping to  diagnose  corneas with suspect keratoconus (SK) </li></ul><ul><li>...
“ Artemis 1” (ArcScan Inc) *Financial Interest www.ArcScan.com
Corneal refractive surgery <ul><li>Cornell University prototype </li></ul><ul><ul><li>50 MHz probe enhanced by digital sig...
Epithelial Thickness Profile:  Normal  v  Keratoconus <ul><li>Average Epithelium All Eyes – Left Eyes Mirrored </li></ul>N...
METHODS:  Theory of Early Keratoconus Artemis KC B-Scan Normal In early keratoconus, epithelial thinning masks the cone Ea...
Are These Topographies Keratoconus? OS OD CASE 2 CASE 1 CASE 3 OD ATLAS Diagnosis
Results Case 1: True keratoconus Case 1 Diagnosis: KERATOCONUS OS Age 25 years Ks (D)  45.25/43.25 @ 76 Rx -1.00 -0.50 x15...
Results Case 2: False Keratoconus Case 2 : Suspect Subclinical KC OD Age 31 years Ks (D)  45.0/44.3 @ 172 Rx -5.00 -0.50 x...
Case 3: Keratoconus With Normal Topography Elevation Front Pachymetry Elevation Back Elevation Front Pachymetry Elevation ...
Are These Topographies Keratoconus? OS OD CASE 2 CASE 1 CASE 3 OD ATLAS Diagnosis Normal Keratoconus Keratoconus Final Dia...
Keratomileusis Early Cohort vs Modern LASIK Keratomileusis LASIK Range of myopia Up to -27.00 D 86% above -7.01 D Rarely t...
Microkeratome accuracy and precision
Thin Flap LASIK
Improvement in flap thickness standard deviation
VisuMax  Femtosecond System
Artemis B-Scan: 6 Months Post LASIK  Artemis B-Scan (above) of VisuMax Flap 6 months post LASIK. Edge detection by I-scan ...
Keratomileusis Early Cohort vs Modern LASIK Keratomileusis LASIK Range of myopia Up to -27.00 D 86% above -7.01 D Rarely t...
What  else  do we know about the long-term safety of LASIK? If ectasia were common, surgeons would know about it
Surgeon Experience – passive surveillance <ul><li>Millions of procedures / 17 years </li></ul><ul><li>We are not experienc...
Radial Keratotomy <ul><li>Lans (Dutch) first described the principles of RK in 1898 </li></ul><ul><li>Sato (Japan) experim...
Radial Keratotomy: Downfall <ul><li>Formal study performed in the US from 1982 </li></ul><ul><li>Prospective Evaluation of...
DLK First Described 1997 <ul><li>Bobby Maddox described “Sands of the Sahara” Syndrome </li></ul><ul><li>ASCRS 1997 </li><...
DLK Cause & Treatment Described 1999 <ul><li>Simon Holland described the cause and treatment of DLK in 1999 </li></ul>Stea...
Keratomileusis Early Cohort vs Modern LASIK Keratomileusis LASIK Range of myopia Up to -27.00 D 86% above -7.01 D Rarely t...
What  else  do we know about the long-term safety of LASIK? Ectasia in the Peer-Reviewed Literature
Ectasia: Peer-Reviewed Literature Is 0.12%-0.66% a realistic rate of ectasia? Report No. of Ectasia/ No. Procedures Percen...
Is 0.12%-0.66% a realistic rate of ectasia? <ul><li>By the end of 2006 </li></ul><ul><ul><li>24.6 million procedures world...
Is 0.12%-0.66% a realistic rate of ectasia? <ul><li>Not consistent with UK experience </li></ul><ul><ul><li>26 ‘refractive...
Ectasia: Peer-Review Literature In Context
Ectasia: Reported Rate In Context <ul><li>The articles reporting a case series of ectasia need to be put into context </li...
Ectasia: Reported Rate In Context Report No. of Ectasia/ No. Procedures Percentage Pallikaris JCRS 2001 19/2,873 0.66% Lyl...
Ectasia: Reported Rate In Context <ul><li>Myopia -14.65  ± 4.40  D </li></ul><ul><li>-8.25 to -22 D </li></ul><ul><li>Flap...
Ectasia: Reported Rate In Context Report No. of Ectasia/ No. Procedures Percentage Pallikaris JCRS 2001 19/2,873 0.66% Lyl...
Ectasia: Reported Rate In Context <ul><li>Myopia -11.69  ± 1.46  D </li></ul><ul><li>-10 to -18 D </li></ul><ul><li>B&L AC...
Ectasia: Reported Rate In Context Report No. of Ectasia/ No. Procedures Percentage Pallikaris JCRS 2001 19/2,873 0.66% Lyl...
Ectasia: Reported Rate In Context <ul><li>Myopia -10.85  ±  3.20  D </li></ul><ul><li>-5.75 to -15.00 D </li></ul><ul><li>...
Ectasia: Reported Rate In Context Report No. of Ectasia/ No. Procedures Percentage Pallikaris JCRS 2001 19/2,873 0.66% Lyl...
Population: Refractive/Pachymetric Distribution <ul><li>Reinstein Population: </li></ul><ul><ul><li>5,212 myopic eyes </li...
Subset of Population: Moria Flap Thickness
Subset of Population: Moria Flap Thickness Which means that 6.3% flaps will be at least 50  µm thicker than intended Inten...
Probability Model for Risk of Ectasia <ul><li>Calculates the expected percentage of eyes obtaining an actual RST below a c...
Probability Model for Risk of Ectasia: Microkeratomes
Probability Model for Risk of Ectasia: Microkeratomes 1 Million Times More Ectasia
Risk of Ectasia: Labeling Bias
Risk of Ectasia: Flap Thickness Standard Deviation
Ectasia: Reported Rate In Context <ul><li>Ectasia Conclusions: </li></ul><ul><li>Reported case series of ectasia are  not ...
Lifetime Risk Factors Source: National Safety Council; http://www.nsc.org/research/odds.aspx Chance of ectasia about 1 in ...
Ectasia: Reported Rate In Context <ul><li>… And remember –  all  the other outcome publications do not report any cases of...
NICE Report – Long-term Safety –  December 2004 <ul><li>“ 1.2 There are concerns about the procedure’s safety in the long-...
NICE Report – Long-term Safety –  March 2006 <ul><li>Statement 1.2 (concerns over long term safety) has been removed </li>...
Continuing Improvements in Safety
Quality of Vision in Corneal Refractive Surgery Gross Safety: Loss of BSCVA
FDA Approved Lasers: Myopia <ul><li>A – First FDA trials </li></ul><ul><li>B – Improved surgeon experience </li></ul><ul><...
Myopia Safety: All Lasers DZ Reinstein
Hyperopia Safety: All Lasers DZ Reinstein
Myopia Efficacy: All Lasers DZ Reinstein Avg Max -4.02 D -13.75 D -3.98 D -14.75 D -3.78 D -9.25 D -4.54 D -12.50 D
Hyperopia Efficacy: All Lasers DZ Reinstein Avg Max +2.34 D +5.00 D +2.35 D +6.75 D +2.64 D +4.75 D +2.67 D +7.25 D
Quality of Vision in Corneal Refractive Surgery Contrast Sensitivity
MEL70 Myopia: Contrast Sensitivity
MEL80 Myopia: Contrast Sensitivity * <ul><li>659 eyes </li></ul><ul><li>Myopia: -4.53  ± 2.14 [-0.40 to -10.15] </li></ul>...
MEL80 Hyperopia: Contrast Sensitivity * * * * Statistically significant improvement (p<0.05) * * <ul><li>210 eyes </li></u...
Complication Rate Experienced Surgeons
Complication Rate – Prof Reinstein FLAP COMPLICATIONS Eyes out of 13,148 % Lose 2 Lines Free Cap 1 (0.01%) 0.0000000% Thin...
What  more  do we know about the long-term safety of LASIK  now ? More long term follow-up studies
Published Long-Term  LASIK  Outcomes -  Myopia 90 eyes Mean SE: -4.85 D B&L Technolas 217 Hansatome Optical zone: 5.79 mm ...
Published Long-Term  LASIK  Outcomes -  Myopia 107 eyes Mean SE: -15.71 D Summit, Technolas 116, MEL60 ACS 160 Optical zon...
Published Long-Term  LASIK  Outcomes -  Myopia 11 eyes Mean SE: -12.96 D MEL60 Draeger lamellar rotor keratome 150 Optical...
Published Long-Term  PRK  Outcomes -  Hyperopia Stability Safety 40 eyes Mean SE: +4.70 D Summit Technology SVS Apex Plus ...
Published Long-Term  LASIK  Outcomes -  Hyperopia Stability Safety 47 eyes Mean SE: +3.58 D Summit Technology SVS Apex Plu...
More Long-term Studies Published <ul><li>Miyai T, Miyata K, Nejima R, Honbo M, Minami K, Amano S.  Comparison of laser in ...
Millions of Procedures Performed <ul><li>By the end of 2007:  28,492,590  laser refractive procedures have been performed ...
LASIK is safe in the long run; looking back at 50 years of lamellar corneal surgery Dan Z Reinstein MD MA(Cantab) FRCSC FR...
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LASIK Surgery is Safe in the Long-Term

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LASIK Surgery is Safe in the Long-Term

  1. 1. LASIK is safe in the long run; looking back at 50 years of lamellar corneal surgery Dan Z Reinstein MD MA(Cantab) FRCSC FRCOphth 1,2,3,4 Timothy J Archer, MA(Oxon), DipCompSci(Cantab) 1 1. London Vision Clinic, London, UK 2. St. Thomas’ Hospital - Kings College, London, UK 3. Weill Medical College of Cornell University, New York, USA 4. Centre Hospitalier National d’Ophtalmologie, (Pr. Laroche) , Paris, France
  2. 2. What do we know about the long-term safety of LASIK?
  3. 3. National Institute for Clinical Excellence – UK “ guidance on the use of new and existing medicines, treatments and procedures within the NHS”
  4. 4. NICE Report – Long-term Safety – December 2004 <ul><li>“ 1.2 There are concerns about the procedure’s safety in the long-term, and current evidence does not appear adequate to support its use without special arrangements for consent and for audit or research.” </li></ul>
  5. 5. Why did NICE come to this conclusion? <ul><li>Over 17 million procedures worldwide by the end of 2004 </li></ul><ul><li>About 8 million procedures in the US alone </li></ul><ul><li>Published long-term safety by the end of 2004? </li></ul><ul><ul><li>5 or more years follow up </li></ul></ul><ul><ul><li>1 PRK paper (total 136 eyes) </li></ul></ul><ul><ul><li>2 LASIK papers (total 158 eyes) </li></ul></ul>
  6. 6. Published Long-Term PRK Outcomes - Myopia Stability Safety 136 eyes Mean SE: -11.40 D Summit Technology UV 200 Optical zone: 4 mm No ectasia
  7. 7. Published Long-Term LASIK Outcomes - Myopia Stability Safety 33 eyes Mean SE: -11.40 D Schwind Keratom I Chiron ALK 130 Optical zone: 5.5 or 6 No ectasia
  8. 8. Published Long-Term LASIK Outcomes - Hyperopia 125 eyes Mean SE: +3.84 D Chiron Technolas Keracor 117C Chiron Corneal Shaper 160 Optical zone: 5.5 mm Stability Safety 5% lost 2 lines No ectasia
  9. 9. Media Response to the NICE Report
  10. 10. NICE Request a Systematic Review
  11. 11. What else do we know about the long-term safety of LASIK? History of LASIK: Keratomileusis
  12. 12. Jose Barraquer: Keratomileusis <ul><li>Jose Barraquer invented a new innovative method of vision correction: Keratomileusis </li></ul>
  13. 13. Jose Barraquer: Keratomileusis <ul><li>Cut and freeze a ~300 µm corneal disc </li></ul>
  14. 14. Jose Barraquer: Keratomileusis <ul><li>Reshape the corneal disc to reduce myopia – shape change calculated using trigonometry </li></ul>
  15. 15. Jose Barraquer: Keratomileusis <ul><li>Reshaping achieved using a lathe </li></ul>
  16. 16. Jose Barraquer: Keratomileusis <ul><li>The corneal disc is sutured back onto the eye </li></ul>
  17. 17. Jose Barraquer: Keratomileusis
  18. 18. Jose Barraquer: Predicting & Shaping the Future <ul><li>Barraquer invented or described nearly all the instruments and techniques now used for modern laser eye surgery </li></ul><ul><ul><li>Microkeratome </li></ul></ul><ul><ul><li>Operating microscope </li></ul></ul><ul><li>Barraquer predicted that lasers instead of lathes would one day be used to reshape the cornea </li></ul>
  19. 19. Keratomileusis: 21-Year Outcomes <ul><li>2,686 myopic eyes treated between 1970 and 1990 </li></ul><ul><li>86.1% of patients had myopia above -7.01 D </li></ul><ul><li>73.6% patients aged 15-35 years, age up to 50 years </li></ul>Chapter 3: Barraquer CC. Correction of ametropias by freezing refractive lamellar surgery: freezing keratomileusis. Thorofare, NJ: Slack Incorporated; 1998 .
  20. 20. Keratomileusis: 21-Year Outcomes <ul><li>Analysis performed on 1,606 eyes that were not reoperated </li></ul><ul><li>60% of eyes were undercorrected at 1 year </li></ul><ul><li>Post-operative myopic progression in all eyes </li></ul><ul><ul><li>Very high myopia </li></ul></ul><ul><ul><li>Extreme surgical technique (compared to modern LASIK) </li></ul></ul><ul><ul><li>Many young patients (under 21) </li></ul></ul>Pre 1 month 3 months 1 year 5 years 10 years 15-21 years 0 -4 -8 -12 Stability -12.00 +1.00 -0.75 -1.75 -3.00 -4.50 -6.50
  21. 21. Keratomileusis: Ectasia <ul><li>45 cases of ectasia out of 1,606 eyes (2.80%) </li></ul><ul><li>Barraquer found ectasia in eyes with </li></ul><ul><ul><li>Preoperatively steep corneas </li></ul></ul><ul><ul><li>Very deep resections </li></ul></ul><ul><li>Following this analysis, Barraquer imposed limits to prevent ectasia </li></ul><ul><ul><li>Cap diameter < 7.5 mm </li></ul></ul><ul><ul><li>Cap thickness < 0.3 mm </li></ul></ul><ul><ul><li>Corneal curvature < 7.4 mm </li></ul></ul><ul><ul><li>IOP control </li></ul></ul>
  22. 22. Keratomileusis Early Cohort vs Modern LASIK Keratomileusis LASIK Range of myopia Up to -27.00 D 86% above -7.01 D Rarely treated above -10.00 D Screening for keratoconus None, keratoconus unknown Topography unavailable Awareness of keratoconus Astigmatism, steep & thin corneas Front & back surface topography Future advances – epithelial thickness profiles, corneal stiffness Depth of keratectomy Deep resection: 300-350 µm in all eyes Original microkeratome: inaccurate & imprecise Microkeratomes more accurate & precise Thin flaps commonly used: avg 110 µm Accurate measurement of corneal thickness and residual stromal bed Low myopia - low ablation depths Ectasia 2.8% from the original cohort ~ 0.06% (more later)
  23. 23. Keratomileusis Early Cohort vs Modern LASIK Keratomileusis LASIK Range of myopia Up to -27.00 D 86% above -7.01 D Rarely treated above -10.00 D Screening for keratoconus None, keratoconus unknown Topography unavailable Awareness of keratoconus Astigmatism, steep & thin corneas Front & back surface topography Future advances – epithelial thickness profiles, corneal stiffness Depth of keratectomy Deep resection: 300-350 µm in all eyes Original microkeratome: inaccurate & imprecise Microkeratomes more accurate & precise Thin flaps commonly used: avg 110 µm Accurate measurement of corneal thickness and residual stromal bed Low myopia - low ablation depths Ectasia 2.8% from the original cohort ~ 0.06% (more later)
  24. 24. What else do we know about the long-term safety of LASIK? Screening for Keratoconus
  25. 25. Topography Screening for Keratoconus
  26. 26. Pentacam Screening for Keratoconus
  27. 27. Ocular Response Analyzer <ul><li>Measurement of the stiffness of the cornea </li></ul><ul><li>Could help diagnose keratoconus </li></ul>Normal Keratoconus
  28. 28. Genetic Testing <ul><li>Aquaporin 5 (AQP5) = important water channel protein </li></ul><ul><li>Absence of AQP5 transcripts in the KC corneas </li></ul>Larger survey of expressed genes in normal cornea would be valuable for further comparisons Water channel defect could contribute to stromal thinning in KC
  29. 29. LASIK / PRK in Keratoconus / Forme Fruste KC? ? Diagnosis LASIK PRK Normal Keratoconus Forme Fruste Keratoconus
  30. 30. Can you do PRK in Forme Fruste Keratoconus? <ul><li>Case reports of ectasia following PRK in FFKC </li></ul><ul><ul><li>Leccisotti A. Corneal ectasia after photorefractive keratectomy. Graefes Arch Clin Exp Ophthalmol 2007;245(6):869-75. </li></ul></ul><ul><ul><li>Randleman JB, Caster AI, Banning CS, Stulting RD. Corneal ectasia after photorefractive keratectomy. J Cataract Refract Surg 2006;32(8):1395-8. </li></ul></ul><ul><ul><li>Malecaze F, Coullet J, Calvas P, Fournie P, Arne JL, Brodaty C. Corneal ectasia after photorefractive keratectomy for low myopia. Ophthalmology 2006;113(5):742-6. </li></ul></ul><ul><ul><li>Lovisolo CF, Fleming JF. Intracorneal ring segments for iatrogenic keratectasia after laser in situ keratomileusis or photorefractive keratectomy. J Refract Surg 2002;18(5):535-41. </li></ul></ul><ul><ul><li>Holland SP, Srivannaboon S, Reinstein DZ. Avoiding serious corneal complications of laser assisted in situ keratomileusis and photorefractive keratectomy. Ophthalmology 2000;107(4):640-52. </li></ul></ul>
  31. 31. Is Forme Fruste Keratoconus a Diagnosis? <ul><li>No! </li></ul><ul><li>Means: “looks like keratoconus” </li></ul><ul><li>Phenotype is unexpressed despite odd topography </li></ul><ul><li>Ideal Solution: </li></ul>FFKC on Topography Diagnostic Technique Not Suitable for Surgery Suitable for LASIK Not Keratoconus Keratoconus
  32. 32. PURPOSE <ul><li>To use epithelial thickness mapping to diagnose corneas with suspect keratoconus (SK) </li></ul><ul><li>To determine the stability of LASIK in corneas with suspect keratoconus confirmed as non-keratoconic </li></ul>FFKC on Topography Diagnostic Technique Not Suitable for Surgery Suitable for LASIK Not Keratoconus Keratoconus
  33. 33. “ Artemis 1” (ArcScan Inc) *Financial Interest www.ArcScan.com
  34. 34. Corneal refractive surgery <ul><li>Cornell University prototype </li></ul><ul><ul><li>50 MHz probe enhanced by digital signal processing </li></ul></ul><ul><ul><li>Pachymetric precision = 1.0 microns </li></ul></ul><ul><ul><li>Meridional scans for 3D data set of individual corneal interfaces </li></ul></ul><ul><ul><li>3D pachymetric topography </li></ul></ul>
  35. 35. Epithelial Thickness Profile: Normal v Keratoconus <ul><li>Average Epithelium All Eyes – Left Eyes Mirrored </li></ul>Normal (n=110) Keratoconus (n=40) N T N T Thinnest 52 µm 44 µm Thickest 58 µm 62 µm Difference 6 µm 12 µm
  36. 36. METHODS: Theory of Early Keratoconus Artemis KC B-Scan Normal In early keratoconus, epithelial thinning masks the cone Earliest epithelial changes occurring in KC are detectable by Epithelial Mapping Keratoconus No Front Surface Cone Anterior stromal surface bulging Back Surface Cone
  37. 37. Are These Topographies Keratoconus? OS OD CASE 2 CASE 1 CASE 3 OD ATLAS Diagnosis
  38. 38. Results Case 1: True keratoconus Case 1 Diagnosis: KERATOCONUS OS Age 25 years Ks (D) 45.25/43.25 @ 76 Rx -1.00 -0.50 x150 BSCVA 20/16 Case 1 : NORMAL Epithelium Stroma Cornea
  39. 39. Results Case 2: False Keratoconus Case 2 : Suspect Subclinical KC OD Age 31 years Ks (D) 45.0/44.3 @ 172 Rx -5.00 -0.50 x 20 BSCVA 20/16 Higher Order Aberrations Case 2 : NORMAL Coma 3.05 µm Sph Ab 0.77 µm HO RMS 0.44 µm Epithelium Stroma Cornea
  40. 40. Case 3: Keratoconus With Normal Topography Elevation Front Pachymetry Elevation Back Elevation Front Pachymetry Elevation Back Case 3 Diagnosis: NORMAL Age 51 years Ks (D) 43.5/42.87 @ 120 (not steep) Rx -4.00 -0.50 x 35 (no cylinder) BSCVA 20/1 2.5 (no drop in BSCVA) Sagital Curvature Total Optical Power Pentacam: Progression of Corneal Thickness Orbscan Pentacam NORMAL Epithelium Stroma Cornea Keratoconus diagnosis may have been missed using surface topography screening alone Case 3 Diagnosis: KERATOCONUS
  41. 41. Are These Topographies Keratoconus? OS OD CASE 2 CASE 1 CASE 3 OD ATLAS Diagnosis Normal Keratoconus Keratoconus Final Diagnosis Including Epithelial Thickness Profile
  42. 42. Keratomileusis Early Cohort vs Modern LASIK Keratomileusis LASIK Range of myopia Up to -27.00 D 86% above -7.01 D Rarely treated above -10.00 D Screening for keratoconus None, keratoconus unknown Topography unavailable Awareness of keratoconus Astigmatism, steep & thin corneas Front & back surface topography Future advances – epithelial thickness profiles, corneal stiffness Depth of keratectomy Deep resection: 300-350 µm in all eyes Original microkeratome: inaccurate & imprecise Microkeratomes more accurate & precise Thin flaps commonly used: avg 110 µm Accurate measurement of corneal thickness and residual stromal bed Low myopia - low ablation depths Ectasia 2.8% from the original cohort ~ 0.06% (more later)
  43. 43. Microkeratome accuracy and precision
  44. 44. Thin Flap LASIK
  45. 45. Improvement in flap thickness standard deviation
  46. 46. VisuMax Femtosecond System
  47. 47. Artemis B-Scan: 6 Months Post LASIK Artemis B-Scan (above) of VisuMax Flap 6 months post LASIK. Edge detection by I-scan digital signal processing (red outline, below) based on raw scan data
  48. 48. Keratomileusis Early Cohort vs Modern LASIK Keratomileusis LASIK Range of myopia Up to -27.00 D 86% above -7.01 D Rarely treated above -10.00 D Screening for keratoconus None, keratoconus unknown Topography unavailable Awareness of keratoconus Astigmatism, steep & thin corneas Front & back surface topography Future advances – epithelial thickness profiles, corneal stiffness Depth of keratectomy Deep resection: 300-350 µm in all eyes Original microkeratome: inaccurate & imprecise Microkeratomes more accurate & precise Thin flaps commonly used: avg 110 µm Accurate measurement of corneal thickness and residual stromal bed Low myopia - low ablation depths Ectasia 2.8% from the original cohort ~ 0.06% (more later)
  49. 49. What else do we know about the long-term safety of LASIK? If ectasia were common, surgeons would know about it
  50. 50. Surgeon Experience – passive surveillance <ul><li>Millions of procedures / 17 years </li></ul><ul><li>We are not experiencing patients returning for follow up complaining of significant myopic regression </li></ul><ul><li>Presentations concerning regression are not flooding the meetings / keranet / forums </li></ul><ul><ul><li>The ophthalmic community acts responsibly to tackle complications </li></ul></ul><ul><ul><ul><li>Radial Keratotomy (RK) </li></ul></ul></ul><ul><ul><ul><li>Diffuse Lamellar Keratitis (DLK) </li></ul></ul></ul><ul><ul><ul><li>TASS </li></ul></ul></ul>
  51. 51. Radial Keratotomy <ul><li>Lans (Dutch) first described the principles of RK in 1898 </li></ul><ul><li>Sato (Japan) experimented in 1930s </li></ul><ul><li>Fyodorov (Russia) popularised the procedure in the 1970s </li></ul><ul><li>He built an RK “conveyor belt”: </li></ul><ul><ul><li>8 beds on a rotating belt </li></ul></ul><ul><ul><li>5 surgeons specialised to specific parts of the procedure </li></ul></ul>National Geographic magazine,&quot;The Sense of Sight&quot;, November 1992
  52. 52. Radial Keratotomy: Downfall <ul><li>Formal study performed in the US from 1982 </li></ul><ul><li>Prospective Evaluation of Radial Keratotomy (PERK) </li></ul><ul><ul><li>28 publications </li></ul></ul><ul><ul><li>After surgery, eyes were progressively more long-sighted: 43% eyes became over 1 diopter more long-sighted after 10 years </li></ul></ul><ul><ul><li>Morning-to-evening fluctuations: mean increase of 0.36 diopters from morning to evening </li></ul></ul>
  53. 53. DLK First Described 1997 <ul><li>Bobby Maddox described “Sands of the Sahara” Syndrome </li></ul><ul><li>ASCRS 1997 </li></ul>Sands of the Sahara DLK
  54. 54. DLK Cause & Treatment Described 1999 <ul><li>Simon Holland described the cause and treatment of DLK in 1999 </li></ul>Steam Sterilizer Holland’s DLK Bypass Dry Heat Sterilizer
  55. 55. Keratomileusis Early Cohort vs Modern LASIK Keratomileusis LASIK Range of myopia Up to -27.00 D 86% above -7.01 D Rarely treated above -10.00 D Screening for keratoconus None, keratoconus unknown Topography unavailable Awareness of keratoconus Astigmatism, steep & thin corneas Front & back surface topography Future advances – epithelial thickness profiles, corneal stiffness Depth of keratectomy Deep resection: 300-350 µm in all eyes Original microkeratome: inaccurate & imprecise Microkeratomes more accurate & precise Thin flaps commonly used: avg 110 µm Accurate measurement of corneal thickness and residual stromal bed Low myopia - low ablation depths Ectasia 2.8% from the original cohort ~ 0.06% (more later)
  56. 56. What else do we know about the long-term safety of LASIK? Ectasia in the Peer-Reviewed Literature
  57. 57. Ectasia: Peer-Reviewed Literature Is 0.12%-0.66% a realistic rate of ectasia? Report No. of Ectasia/ No. Procedures Percentage Pallikaris JCRS 2001 19/2,873 0.66% Lyle JCRS 2001 1/332 0.30% Rad JRS 2004 14/6,941 0.20% Reinstein JRS 2006 6/5,212 0.12%
  58. 58. Is 0.12%-0.66% a realistic rate of ectasia? <ul><li>By the end of 2006 </li></ul><ul><ul><li>24.6 million procedures worldwide </li></ul></ul><ul><ul><li>10.9 million procedures in the USA </li></ul></ul><ul><li>Not consistent with our experience </li></ul><ul><ul><li>Total of about 110 cases of ectasia in peer-reviewed literature </li></ul></ul>Rate of Ectasia Expected No. of Ectasia ~ Worldwide Expected No. of Ectasia ~ USA 0.12% 29,520 13,080 0.20% 49,200 21,800 0.30% 73,800 32,700 0.66% 162,360 71,940
  59. 59. Is 0.12%-0.66% a realistic rate of ectasia? <ul><li>Not consistent with UK experience </li></ul><ul><ul><li>26 ‘refractive surgery’ corneal transplants in the UK between 1999 and 2004 </li></ul></ul><ul><li>Conservative estimate: 300,000 LASIK procedures </li></ul><ul><li>Assume worst case that all 26 transplants were for ectasia </li></ul><ul><li>Assume 1 in 5 ectasia patients managed with contact lenses </li></ul><ul><li>Translate to a 0.011% rate of ectasia </li></ul><ul><ul><li>60 times less than the maximum reported rate of 0.66% </li></ul></ul>
  60. 60. Ectasia: Peer-Review Literature In Context
  61. 61. Ectasia: Reported Rate In Context <ul><li>The articles reporting a case series of ectasia need to be put into context </li></ul><ul><ul><li>What type of patients were operated on? </li></ul></ul><ul><ul><li>What instruments and protocols were used for surgery? </li></ul></ul><ul><li>Known Risk Factors for Ectasia: </li></ul><ul><ul><li>Operating on keratoconus </li></ul></ul><ul><ul><li>Excessive keratectomy </li></ul></ul><ul><ul><ul><li>Treatment of high myopia </li></ul></ul></ul><ul><ul><ul><li>Retreatments (especially without RST measurement) </li></ul></ul></ul><ul><ul><ul><li>Imprecise microkeratomes </li></ul></ul></ul>
  62. 62. Ectasia: Reported Rate In Context Report No. of Ectasia/ No. Procedures Percentage Pallikaris JCRS 2001 19/2,873 0.66% Lyle JCRS 2001 1/332 0.30% Rad JRS 2004 14/6,941 0.20% Reinstein JRS 2006 6/5,212 0.12%
  63. 63. Ectasia: Reported Rate In Context <ul><li>Myopia -14.65 ± 4.40 D </li></ul><ul><li>-8.25 to -22 D </li></ul><ul><li>FlapMaker microkeratome </li></ul>
  64. 64. Ectasia: Reported Rate In Context Report No. of Ectasia/ No. Procedures Percentage Pallikaris JCRS 2001 19/2,873 0.66% Lyle JCRS 2001 1/332 0.30% Rad JRS 2004 14/6,941 0.20% Reinstein JRS 2006 6/5,212 0.12%
  65. 65. Ectasia: Reported Rate In Context <ul><li>Myopia -11.69 ± 1.46 D </li></ul><ul><li>-10 to -18 D </li></ul><ul><li>B&L ACS microkeratome </li></ul>
  66. 66. Ectasia: Reported Rate In Context Report No. of Ectasia/ No. Procedures Percentage Pallikaris JCRS 2001 19/2,873 0.66% Lyle JCRS 2001 1/332 0.30% Rad JRS 2004 14/6,941 0.20% Reinstein JRS 2006 6/5,212 0.12%
  67. 67. Ectasia: Reported Rate In Context <ul><li>Myopia -10.85 ± 3.20 D </li></ul><ul><li>-5.75 to -15.00 D </li></ul><ul><li>Moria CB microkeratome </li></ul>
  68. 68. Ectasia: Reported Rate In Context Report No. of Ectasia/ No. Procedures Percentage Pallikaris JCRS 2001 19/2,873 0.66% Lyle JCRS 2001 1/332 0.30% Rad JRS 2004 14/6,941 0.20% Reinstein JRS 2006 6/5,212 0.12%
  69. 69. Population: Refractive/Pachymetric Distribution <ul><li>Reinstein Population: </li></ul><ul><ul><li>5,212 myopic eyes </li></ul></ul><ul><ul><li>Moria LSK-One “130” with the “-1” head </li></ul></ul><ul><ul><li>NIDEK EC5000 excimer laser </li></ul></ul><ul><ul><li>6 known cases of ectasia (= 0.115%) </li></ul></ul>
  70. 70. Subset of Population: Moria Flap Thickness
  71. 71. Subset of Population: Moria Flap Thickness Which means that 6.3% flaps will be at least 50 µm thicker than intended Intended Flap Thickness 160 µm Average Flap Thickness 163.6 µm Flap Thickness Bias +3.6 µm Flap Thickness Standard Deviation 30.3 µm
  72. 72. Probability Model for Risk of Ectasia <ul><li>Calculates the expected percentage of eyes obtaining an actual RST below a chosen cut-off </li></ul>%
  73. 73. Probability Model for Risk of Ectasia: Microkeratomes
  74. 74. Probability Model for Risk of Ectasia: Microkeratomes 1 Million Times More Ectasia
  75. 75. Risk of Ectasia: Labeling Bias
  76. 76. Risk of Ectasia: Flap Thickness Standard Deviation
  77. 77. Ectasia: Reported Rate In Context <ul><li>Ectasia Conclusions: </li></ul><ul><li>Reported case series of ectasia are not representative of the normal LASIK population </li></ul><ul><li>Virtually all reported cases can be explained by known risk factors </li></ul><ul><ul><li>Pre-operative keratoconus </li></ul></ul><ul><ul><li>Excessive keratectomy </li></ul></ul><ul><ul><li>Imprecise instruments, particularly microkeratomes </li></ul></ul><ul><li>NICE Systematic Review (April 2005) : “published ectasia case series would have been only 0.06% had modern protocols been used” </li></ul>
  78. 78. Lifetime Risk Factors Source: National Safety Council; http://www.nsc.org/research/odds.aspx Chance of ectasia about 1 in 2,000 One Year Odds Lifetime Odds All injury deaths 1,765 23 All accident deaths 2,794 37 Motor vehicle 6,078 80 Pedestrian 44,009 578 Fire & flames 70,913 932 Poisoning by venomous animals, plants 3,901,235 51,265 Dog bite 11,534,087 151,565 Lightning 4,210,857 55,333 Choking 82,746 1,087 Drowning in bathtub 803,891 10,564 Struck by falling object 362,410 4,762 Firearm missile 233,937 3,074 Fireworks 29,476,000 387,332 Children murdered by mothers 226,728 2,979 Children murdered by fathers 26,527,135 348,582
  79. 79. Ectasia: Reported Rate In Context <ul><li>… And remember – all the other outcome publications do not report any cases of ectasia </li></ul><ul><li>DZ Reinstein has performed 13,148 LASIK procedures with 0 cases of ectasia as of 1 st October 2008 </li></ul>“ Ectasia Rate” Expected # of Cases 0.66% 87 0.20% 26 0.10% 13
  80. 80. NICE Report – Long-term Safety – December 2004 <ul><li>“ 1.2 There are concerns about the procedure’s safety in the long-term, and current evidence does not appear adequate to support its use without special arrangements for consent and for audit or research.” </li></ul>
  81. 81. NICE Report – Long-term Safety – March 2006 <ul><li>Statement 1.2 (concerns over long term safety) has been removed </li></ul>
  82. 82. Continuing Improvements in Safety
  83. 83. Quality of Vision in Corneal Refractive Surgery Gross Safety: Loss of BSCVA
  84. 84. FDA Approved Lasers: Myopia <ul><li>A – First FDA trials </li></ul><ul><li>B – Improved surgeon experience </li></ul><ul><li>C – Advancement in technology </li></ul>A B C
  85. 85. Myopia Safety: All Lasers DZ Reinstein
  86. 86. Hyperopia Safety: All Lasers DZ Reinstein
  87. 87. Myopia Efficacy: All Lasers DZ Reinstein Avg Max -4.02 D -13.75 D -3.98 D -14.75 D -3.78 D -9.25 D -4.54 D -12.50 D
  88. 88. Hyperopia Efficacy: All Lasers DZ Reinstein Avg Max +2.34 D +5.00 D +2.35 D +6.75 D +2.64 D +4.75 D +2.67 D +7.25 D
  89. 89. Quality of Vision in Corneal Refractive Surgery Contrast Sensitivity
  90. 90. MEL70 Myopia: Contrast Sensitivity
  91. 91. MEL80 Myopia: Contrast Sensitivity * <ul><li>659 eyes </li></ul><ul><li>Myopia: -4.53 ± 2.14 [-0.40 to -10.15] </li></ul>* * * * Statistically significant improvement (p<0.05) * * * * *
  92. 92. MEL80 Hyperopia: Contrast Sensitivity * * * * Statistically significant improvement (p<0.05) * * <ul><li>210 eyes </li></ul><ul><li>Hyperopia: +2.51 ± 1.16 [+0.25 to +5.00] </li></ul>*
  93. 93. Complication Rate Experienced Surgeons
  94. 94. Complication Rate – Prof Reinstein FLAP COMPLICATIONS Eyes out of 13,148 % Lose 2 Lines Free Cap 1 (0.01%) 0.0000000% Thin Flap 2 (0.02%) 0.0000000% Incomplete Flap (no ablation) 6 (0.05%) 0.0000000% Corneal Perforation 0 (0.00%) 0.0000000% Blindness (total loss of vision) 0 (0.00%) 0.0000000% Corneal scarring reducing vision 0 (0.00%) 0.0000000% Inflammation with decrease of vision 1 (0.01%) 0.0000000% Infection 0 (0.00%) 0.0000000% Epithelial Ingrowth (requiring further surgery) 21 (0.19%) 0.0000000% Need for corneal transplantation 0 (0.00%) 0.0000000% Keratectasia 0 (0.00%) 0.0000000% LASER COMPLICATIONS Eyes out of 13,148 % Lose 2 Lines Visually sig. decentrations 0 (0.00%) 0.0000000% Laser parameter data entry error 3 (0.03%) 0.0000000%
  95. 95. What more do we know about the long-term safety of LASIK now ? More long term follow-up studies
  96. 96. Published Long-Term LASIK Outcomes - Myopia 90 eyes Mean SE: -4.85 D B&L Technolas 217 Hansatome Optical zone: 5.79 mm Stability Safety 0.0% lost 2 lines 7% lost 1 line 51% no change 42% gain 1 or more lines No ectasia 0 to -3 D -6 to -13 D -3 to -6 D All
  97. 97. Published Long-Term LASIK Outcomes - Myopia 107 eyes Mean SE: -15.71 D Summit, Technolas 116, MEL60 ACS 160 Optical zone: 6 mm Stability Safety
  98. 98. Published Long-Term LASIK Outcomes - Myopia 11 eyes Mean SE: -12.96 D MEL60 Draeger lamellar rotor keratome 150 Optical zone: 5 mm Stability Safety 0.00 -0.50 -0.96 -1.05 -1.14 -12.96
  99. 99. Published Long-Term PRK Outcomes - Hyperopia Stability Safety 40 eyes Mean SE: +4.70 D Summit Technology SVS Apex Plus Optical zone: 6 mm 5% lost 2 lines 30% lost 1 line 65% no change or improved No ectasia
  100. 100. Published Long-Term LASIK Outcomes - Hyperopia Stability Safety 47 eyes Mean SE: +3.58 D Summit Technology SVS Apex Plus Moria LSK-One 180 Optical Zone: 6 mm 0.0% lost 2 lines 2.1% lost 1 line 57.4% no change 40.5% gain 1 or more lines No ectasia
  101. 101. More Long-term Studies Published <ul><li>Miyai T, Miyata K, Nejima R, Honbo M, Minami K, Amano S. Comparison of laser in situ keratomileusis and photorefractive keratectomy results: long-term follow-up . J Cataract Refract Surg. 2008;34:1527-1531. </li></ul><ul><li>Kezirian GM, Moore CR, Stonecipher KG. Four-year postoperative results of the US ALLEGRETTO WAVE clinical trial for the treatment of hyperopia . J Refract Surg. 2008;24:S431-438. </li></ul><ul><li>Alio JL, Ortiz D, Muftuoglu O, Garcia MJ. Ten years after Photorefractive Keratectomy (PRK) and Laser In Situ Keratomileusis (LASIK) for Moderate to High Myopia (Control-Matched Study) . Br J Ophthalmol. 2008. </li></ul><ul><li>Desai RU, Jain A, Manche EE. Long-term follow-up of hyperopic laser in situ keratomileusis correction using the Star S2 excimer laser. J Cataract Refract Surg. 2008;34:232-237. </li></ul><ul><li>Alio JL, Muftuoglu O, Ortiz D, Perez-Santonja JJ, Artola A, Ayala MJ, Garcia MJ, de Luna GC. Ten-year follow-up of laser in situ keratomileusis for myopia of up to -10 diopters. Am J Ophthalmol. 2008;145:46-54. </li></ul><ul><li>Alio JL, Muftuoglu O, Ortiz D, Perez-Santonja JJ, Artola A, Ayala MJ, Garcia MJ, de Luna GC. Ten-year follow-up of laser in situ keratomileusis for high myopia. Am J Ophthalmol. 2008;145:55-64. </li></ul>
  102. 102. Millions of Procedures Performed <ul><li>By the end of 2007: 28,492,590 laser refractive procedures have been performed </li></ul>Data courtesy Dave Harmon (MarketScope)
  103. 103. LASIK is safe in the long run; looking back at 50 years of lamellar corneal surgery Dan Z Reinstein MD MA(Cantab) FRCSC FRCOphth 1,2,3,4 Timothy J Archer, MA(Oxon), DipCompSci(Cantab) 1 1. London Vision Clinic, London, UK 2. St. Thomas’ Hospital - Kings College, London, UK 3. Weill Medical College of Cornell University, New York, USA 4. Centre Hospitalier National d’Ophtalmologie, (Pr. Laroche) , Paris, France Thank You

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