High Myopia Final CZM Dubai_2011

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  • 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. 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. 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. 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. Why was spherical aberrationincreasing?
  • 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. Optimization• Biomechanics VHF digital ultrasound ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 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. 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. 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. Free lunch?
  • 12. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 13. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 14. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 15. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 16. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 17. ESCRS 2002, DZ Reinstein: Z4,0-Slider (aka Q-slider) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 18. Free Lunch?• Increasing ablation zone diameter• Adding asphericity • Increases central ablation depth • No “Free Lunch” ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 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. Wavefront-Guided Treatmentof Spherical Aberration
  • 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. 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. 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. 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. 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. Induction of Spherical Aberration Complaint of NVD post RS1 1 ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 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. CENTRAL ISLANDS:-5.50 D ablationDiplopia first weekSlow resolution over 2 weeksSlides courtesy Gordon Balazsi, MD ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 29. CENTRAL ISLANDS:-5.00 D ablationSlides courtesy Gordon Balazsi, MD ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 30. Ablation Depth with SA Pre-Compensation ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 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. 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. Ablation Depth for New Profile ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 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. 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. Outcomes
  • 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. 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. 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. 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. 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. 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. 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. MEL80 High Myopia: Contrast Sensitivity * * Statistically significant (p<0.05) ©DZ Reinstein 2009 dzr@londonvisionclinic.com
  • 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. 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. Thank You Very high myopic LASIK using new hybrid aspheric profiles Dan Z Reinstein MD MA(Cantab) FRCSC FRCOphth1,2,3,4