Very high myopic LASIK using new     hybrid aspheric profilesDan Z Reinstein MD MA(Cantab) FRCSC FRCOphth1,2,3,41. London ...
First Results: Munnerlyn Ablation Profile• Early ablation profiles often induced:   – Night Vision disturbances   – Decrea...
Ablation Profile Design: Larger Optical Zone    Example: 5-mm Munnerlyn ablation for -6.00 D (1993 Summit Laser)       Top...
Ablation Profile Design: Aspheric Profiles• Barraquer 1980   – Suggested parabolic keratomileusis• Seiler 1993 – PRK asphe...
Why was spherical aberrationincreasing?
Optimization: Fluence correction• Fluence correction: Topography  – Beam reflection compensation  – Beam projection compen...
Optimization• Biomechanics                 VHF digital ultrasound                                                 ©DZ Rein...
Reinstein et al. Journal of Refractive SurgeryArtemis C12 Display                                              2000 Jul-Au...
Examples of Peripheral Stromal Thickening                                                      Peripheral Stromal         ...
Corneal Biomechanical Trade-off• Hyperopic shift induced by   – Central flattening due to peripheral tissue removal• Myopi...
Free lunch?
ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider)                                                   ©DZ Reinstein 2009 ...
ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider)                                                   ©DZ Reinstein 2009 ...
ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider)                                                   ©DZ Reinstein 2009 ...
ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider)                                                   ©DZ Reinstein 2009 ...
ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider)                                                   ©DZ Reinstein 2009 ...
ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider)                                                   ©DZ Reinstein 2009 ...
Free Lunch?• Increasing ablation zone diameter• Adding asphericity                                • Increases central     ...
550 µm Pachymetry: Forces Compromise• Modern aspheric ablation profiles still induce spherical  aberration• Problem: high ...
Wavefront-Guided Treatmentof Spherical Aberration
Correlation of Contrast with Wavefront           Spherical Aberration                                              Contras...
Pre-Compensate for Spherical Aberration• “Q-slider”   – (WaveLight)• Wavefront-guided ablation   – Includes pre-op spheric...
Patient 1, OD                   -7.13 D Corrected6mm       OSA               6mm         OSAComa     0.09 µm            Co...
Patient 1, OS                   -9.00 D Corrected6mm       OSA               6mm         OSAComa     0.03 µm            Co...
Patient 1, Night Vision                  Pre Op                   Post Op                      Rx Treated             OD  ...
Induction of Spherical Aberration                                    Complaint of NVD post RS1 1                          ...
Limits to SA Pre-Compensation• Excess spherical aberration pre-compensation can  lead to “central islands”         TMS    ...
CENTRAL ISLANDS:-5.50 D ablationDiplopia first weekSlow resolution over 2 weeksSlides courtesy Gordon Balazsi, MD         ...
CENTRAL ISLANDS:-5.00 D ablationSlides courtesy Gordon Balazsi, MD                                            ©DZ Reinstei...
Ablation Depth with SA Pre-Compensation                                        ©DZ Reinstein 2009                         ...
New Profile for High Myopia• Non-linear aspheric ablation profile:   – Increased peripheral ablation (not ↑ z(4,0))   – Re...
New Profile: “Free Lunch”• Over-corrected by +0.50 D compared with theory• Ablation depth lower than expected             ...
Ablation Depth for New Profile                                        ©DZ Reinstein 2009                                 d...
Femtosecond Lasers• Femtosecond lasers have improved flap thickness  reproducibility (VisuMax SD: 8 µm)• We can create thi...
Example RST Planning     Refraction                 -10.75 D sph     Pachymetry                 509 µm     Flap Thickness ...
Outcomes
New Profile for High Myopia• Patients  –   Myopia SEQ -9.51 ± 1.32 D -8.00 up to -14.50 D  –   Myopia max merid -10.18 ± 1...
Advantages of Two Stage Procedure• Increased safety   – Greater RST for primary treatment   – Artemis measured RST to calc...
Topography Guided Retreatment                               Pre       Post      Reduced                     Sph Ab   0.48 ...
MEL80 High Myopia: Accuracy                     Attempted vs. Achieved Spherical Equivalent         -14     )             ...
MEL80 High Myopia: AccuracyWithin ±0.50                   71%DWithin ±1.00                   94%      Accuracy: Within Ran...
Monocular Efficacy(excluding eyes not intended plano)n=176                             Efficacy: Monocular UCVA           ...
MEL80 High Myopia: Safety – BSCVAn=220                        Safety: Lines Change BSCVA        60%                       ...
MEL80 High Myopia: Contrast Sensitivity                                         *  * Statistically significant (p<0.05)   ...
Stability           2.00         ) 0.00         D         (         t         n         e         l -2.00         a       ...
Take Home Message• Know your spherical aberration induction per dioptre• Measure pre-op spherical aberration• Check whethe...
Thank You Very high myopic LASIK using new hybrid aspheric profiles Dan Z Reinstein MD MA(Cantab) FRCSC FRCOphth1,2,3,4
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High Myopia Final CZM Dubai_2011

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High Myopia Final CZM Dubai_2011

  1. 1. Very high myopic LASIK using new hybrid aspheric profilesDan Z Reinstein MD MA(Cantab) FRCSC FRCOphth1,2,3,41. London Vision Clinic, London, UK2. St. Thomas’ Hospital - Kings College, London, UK3. Weill Medical College of Cornell University, New York, USA4. Centre Hospitalier National d’Ophtalmologie, (Pr. Laroche) , Paris, France
  2. 2. First Results: Munnerlyn Ablation Profile• Early ablation profiles often induced: – Night Vision disturbances – Decreased contrast sensitivity• Limited the range of treatable refractions• PROBLEM: Induction of spherical aberration Eur J Ophthalmol. 1994 Jan-Mar;4(1):43-51. Night vision after excimer laser photorefractive keratectomy: haze and halos. OBrart DP, Lohmann CP, Fitzke FW, Smith SE, Kerr-Muir MG, Marshall J. ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  3. 3. Ablation Profile Design: Larger Optical Zone Example: 5-mm Munnerlyn ablation for -6.00 D (1993 Summit Laser) Topography Wavefront Z(4,0) (OSA) 1.18 µm J Refract Corneal Surg. 1994 Mar-Apr;10(2):87-94. Excimer laser photorefractive keratectomy for myopia: comparison of 4.00- and 5.00-millimeter ablation zones. OBrart DP, Gartry DS, Lohmann CP, Muir MG, Marshall J. Arch Ophthalmol. 1995 Apr;113(4):438-43. The effects of ablation diameter on the outcome of excimer laser photorefractive keratectomy. A prospective, randomized, double-blind study. OBrart DP, Corbett MC, Lohmann CP, Kerr Muir MG, Marshall J. ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  4. 4. Ablation Profile Design: Aspheric Profiles• Barraquer 1980 – Suggested parabolic keratomileusis• Seiler 1993 – PRK aspheric profiles – Less starburst & halos – Larger effective clear optical zone size ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  5. 5. Why was spherical aberrationincreasing?
  6. 6. Optimization: Fluence correction• Fluence correction: Topography – Beam reflection compensation – Beam projection compensation J Refract Surg 2001;17(5):S584-7. Influence of corneal curvature on calculation of ablation patterns used in photorefractive laser surgery. Mrochen M, Seiler T. ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  7. 7. Optimization• Biomechanics VHF digital ultrasound ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  8. 8. Reinstein et al. Journal of Refractive SurgeryArtemis C12 Display 2000 Jul-Aug;16:414-30 VHF digital ultrasound Roberts C. The cornea is not a piece of plastic. JRS 2000; 16:407-413 ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  9. 9. Examples of Peripheral Stromal Thickening Peripheral Stromal Thickening Central Flattening Roberts C. The cornea is not a piece of plastic. ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  10. 10. Corneal Biomechanical Trade-off• Hyperopic shift induced by – Central flattening due to peripheral tissue removal• Myopic shift induced by Pre-Op – Epithelial thickening – Bowing of the back surface Epithelial thickening Post-Op Back surface bowing ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  11. 11. Free lunch?
  12. 12. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  13. 13. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  14. 14. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  15. 15. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  16. 16. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  17. 17. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  18. 18. Free Lunch?• Increasing ablation zone diameter• Adding asphericity • Increases central ablation depth • No “Free Lunch” ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  19. 19. 550 µm Pachymetry: Forces Compromise• Modern aspheric ablation profiles still induce spherical aberration• Problem: high myopic corrections may result in NVDs Attempted Spherical Equivalent vs. Change in Z(4,0) Coefficient ASA Treatments 0.7 y = -0.059x - 0.0136 0.6 ) R² = 0.6444 A S O 0.5 , m µ ( t 0.4 n e i c i f f 0.3 e o C 0.2 ) 0 , 4 ( Z 0.1 n i e g 0.0 n a h C -0.1 -0.2 0.00 -1.00 -2.00 -3.00 -4.00 -5.00 -6.00 -7.00 -8.00 -9.00 -10.00 Attempted Spherical Equivalent (Diopters) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  20. 20. Wavefront-Guided Treatmentof Spherical Aberration
  21. 21. Correlation of Contrast with Wavefront Spherical Aberration Contrast Sensitivity p 900 1.2 800 t 1.1 s 700 a o r i t t 1.0 600 n a o R C y 0.9 500 t d i e v z i t2 400 i i l s a n 0.8 m 300 m r e µ o S 0.7 200 N 0.6 100 0.5 0 3 cpd 6 cpd 12 cpd 18 cpd Pre CRS-M Post CRSM- Control Pre Control Post Control Pre 1.02 1.02 1.03 1.04 Repair Repair Control Post 1.04 1.01 1.03 1.01Sph Ab Area 122 276 563 410 Pre CRSM-Repair 0.85 0.84 0.77 0.75 Post CRSM-Repair 1.04 1.02 1.02 1.00 • 27% Gross Reduction • 53% Net Reduction (cf tolerable level) • Tolerable level ~0.56 µm @ 6mm ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  22. 22. Pre-Compensate for Spherical Aberration• “Q-slider” – (WaveLight)• Wavefront-guided ablation – Includes pre-op spherical aberration – Effect dependent on pre-op spherical aberration• Our Approach: Include an “artificial” wavefront – Isolate spherical aberration: Z(4,0) as the only coefficient – Z(4,0) coefficient proportional to expected induction – Increase Z(4,0) coefficient: wavefront only 20% effective ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  23. 23. Patient 1, OD -7.13 D Corrected6mm OSA 6mm OSAComa 0.09 µm Coma 0.04 µmSph Ab 0.48 µm Sph Ab 0.42 µmHO RMS 0.59 µm HO RMS 0.52 µm ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  24. 24. Patient 1, OS -9.00 D Corrected6mm OSA 6mm OSAComa 0.03 µm Coma 0.05 µmSph Ab 0.49 µm Sph Ab 0.55 µmHO RMS 0.57 µm HO RMS 0.60 µm ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  25. 25. Patient 1, Night Vision Pre Op Post Op Rx Treated OD -6.50 -1.25 x 178 OS -8.25 -1.50 x 17 ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  26. 26. Induction of Spherical Aberration Complaint of NVD post RS1 1 ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  27. 27. Limits to SA Pre-Compensation• Excess spherical aberration pre-compensation can lead to “central islands” TMS WASCA (zonal) EpitheliumOD ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  28. 28. CENTRAL ISLANDS:-5.50 D ablationDiplopia first weekSlow resolution over 2 weeksSlides courtesy Gordon Balazsi, MD ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  29. 29. CENTRAL ISLANDS:-5.00 D ablationSlides courtesy Gordon Balazsi, MD ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  30. 30. Ablation Depth with SA Pre-Compensation ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  31. 31. New Profile for High Myopia• Non-linear aspheric ablation profile: – Increased peripheral ablation (not ↑ z(4,0)) – Reduced induction of spherical aberration – Free lunch: some myopia corrected due to central flattening Extend this concept further to promote central flattening Ability to correct high myopia without risk of NVDs Peripheral Stromal Thickening Central Flattening Roberts C. The cornea is not a piece of plastic. ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  32. 32. New Profile: “Free Lunch”• Over-corrected by +0.50 D compared with theory• Ablation depth lower than expected Attempted vs. Achieved Spherical Equivalent -14 y = 0.9958x - 0.5106 ) -13 R² = 0.9291 s r e t p-12 o i D ( t -11 n e l a v -10 i u q E -9 l a c i r e -8 h p S d -7 e v e i h -6 c A -5 -6 -7 -8 -9 -10 -11 -12 -13 -14 Attempted Spherical Equivalent (Diopters) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  33. 33. Ablation Depth for New Profile ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  34. 34. Femtosecond Lasers• Femtosecond lasers have improved flap thickness reproducibility (VisuMax SD: 8 µm)• We can create thinner flaps (VisuMax: 80 µm)• Thinner flaps extends the range of myopia in LASIK Pre-release online ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  35. 35. Example RST Planning Refraction -10.75 D sph Pachymetry 509 µm Flap Thickness (VisuMax) 80 µm Ablation Depth 135 µm Predicted RST 296 µm ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  36. 36. Outcomes
  37. 37. New Profile for High Myopia• Patients – Myopia SEQ -9.51 ± 1.32 D -8.00 up to -14.50 D – Myopia max merid -10.18 ± 1.48 D -8.00 up to -16.00 D – Cylinder -1.32 ± 1.10 D up to -6.25 D – 220 eyes – 1 year follow up• Retreatments – 45% eyes treated as “two-stage” – Enhancement rate (non two-stage): 35% ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  38. 38. Advantages of Two Stage Procedure• Increased safety – Greater RST for primary treatment – Artemis measured RST to calculate retreatment – Option to retreat using topography-guided profile• More accurate result• Patient has lower expectations ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  39. 39. Topography Guided Retreatment Pre Post Reduced Sph Ab 0.48 µm 0.28 µm 41% HO RMS 0.72 µm 0.57 µm 21% ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  40. 40. MEL80 High Myopia: Accuracy Attempted vs. Achieved Spherical Equivalent -14 ) y = 1.0726x + 0.8394 s r e t -13 R² = 0.8759 p o i D ( t -12 n e l a v i -11 u q E l a c i -10 r e h p S -9 d e v e i h -8 c A -7 -7 -8 -9 -10 -11 -12 -13 -14 Attempted Spherical Equivalent (Diopters) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  41. 41. MEL80 High Myopia: AccuracyWithin ±0.50 71%DWithin ±1.00 94% Accuracy: Within Range of IntendedD 35% 33% 30% 25% s 25% e y E 20% e 15% g 15% 13% a t n e 10% c r 7% e P 5% 3% 0% 1% 1% 0% -2.00 -1.50 -1.00 -0.50 -0.13 0.14 +0.51 +1.01 +1.51 To - To - To - To - To To To To To 1.51 1.01 0.51 0.14 0.13 +0.50 +1.00 +1.50 +2.00 Accuracy 0% 3% 15% 33% 25% 13% 7% 1% 1% Accuracy of Spherical Equivalent ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  42. 42. Monocular Efficacy(excluding eyes not intended plano)n=176 Efficacy: Monocular UCVA 100% 99% 99% 99% 100% 97% 90% 83% 80% s e y E 60% e 47% g a t n 40% e 28% c r e P 20% 11% 1% 0% 20/12.5 20/16 20/20 20/25 20/32 20/40 20/63 Pre BSCVA 1% 28% 83% 100% Efficacy 11% 47% 90% 97% 99% 99% 99% Monocular UCVA ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  43. 43. MEL80 High Myopia: Safety – BSCVAn=220 Safety: Lines Change BSCVA 60% 52% s 40% e y 40% E e g a t n e 20% c r e P N=4 6% 2% 0.0% 0.0% 0% Loss 3 or No Gain 2 or Loss 2 Loss 1 Gain 1 More Change More Safety 0.0% 0.0% 2% 40% 52% 6% Lines Change BSCVA ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  44. 44. MEL80 High Myopia: Contrast Sensitivity * * Statistically significant (p<0.05) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  45. 45. Stability 2.00 ) 0.00 D ( t n e l -2.00 a v i u q E -4.00 l a c i r e -6.00 h p S -8.00 -10.00 -12.00 3 Mo 6 Mo 12 Mo 24 Mo Pre-op 1 Day 1 Month 3 Months 6 Months 1 Year 2 YearsMean±SD -9.60±1.39 +0.41±0.82 +0.01±0.82 -0.18±0.86 -0.22±0.91 -0.04±0.91 -0.06±1.07# eyes 220 199 201 188 158 124 45 ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  46. 46. Take Home Message• Know your spherical aberration induction per dioptre• Measure pre-op spherical aberration• Check whether spherical aberration is going to go beyond the threshold – Use SA pre-compensation – Use a 2-stage procedure (wavefront / topography guided repair if necessary as second treatment)• Caution with predicted RST – Reduce potential errors – Measure pachymetry with high repeatability instrument – Use high reproducibility flap creation technique – Always include flap thickness bias ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  47. 47. Thank You Very high myopic LASIK using new hybrid aspheric profiles Dan Z Reinstein MD MA(Cantab) FRCSC FRCOphth1,2,3,4

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