From freezing to photoablation<br />The evolution  of lasik<br />J. Alberto Martinez, M.D.<br /> Visionary Ophthalmology<b...
OUTLINE<br />Incisional refractive surgery<br />Lamellar refractive surgery<br />Non-excimer laser lamellar refractive sur...
Martinez’ classification of refractive surgery<br />Corneal procedures<br />Conjuntival procedures<br />Scleral procedures...
Corneal procedures<br />Incisional procedures: RK, AK, LRI<br />Surface reshaping: PRK ( PTK), CK orthokeratology<br />Str...
Radial Keratotomy<br />Tsutomu Sato of Japan, 1933: 40-45 endothelial side cuts: Corneal edema<br />
Cornea: RK, AK/LRI <br />RK reshapes the cornea  by relaxing steep meridians<br />Advantages: Quick, inexpensive<br />Disa...
Radial Keratotomy<br />Early 1970s, Dr. Yenaliev,<br />Durnev and Fyodorov: External<br />	incisions only<br />Dr Fyodorov...
Incisional refractive surgery (IRS)<br />Outdated because:<br />Unpredictability<br />Limited range of effect (minor myopi...
Dr. Luis Ruiz, RK innovator<br />
CK®<br />Thermokeratoplasty: technique that uses RF energy to heat and reshape the cornea<br />
Lamellar Refractive surgery<br />Conceived and developed By <br />Dr. Jose Barraquer<br />Bogota, Colombia.<br />Voted as ...
Ley de Espesores – Law of Thicknes<br />
Keratomilieusis<br />
The Microkeratome<br />
Automated Lamellar Keratoplasty, ALK<br />
ExcimerLaser  <br />Developed at IBM in 1976 to etch microchips<br />First introduced by Stephen Trokel in 1983 <br />LASI...
EXCIMER LASER<br />
Excimer Laser in ALK<br />1990 LASIK  was born as the “flap and Zap” Dr. Steven Slade <br />1995 LASIK approved by the FDA...
ALK + Excimer = LASIK<br />
First Generation Excimer lasers<br />
Second Generation Excimer Lasers<br />
Wavescan: Wavefront scan<br />
Customized Ablations<br />
WAVEFRONT GUIDED   VS.WAVEFRONT OPTIMIZED<br />
WavefrontGUIDEDTreatment<br />Wavefront measurement ( lower order aberrations: <br />Defocus (sphere) and Astigmatism (cyl...
WavefrontGUIDEDTreatment<br />A wavefrontrefration with small pupils<br />Plus larger diameter treatments=<br />High techn...
Wavefront Optimized excimerlasers: Latest generation of lasers<br />ALLEGRETTO WAVE® LASER FEATURES<br />
Wavefront Optimized<br />Latest lasers: Smaller scanning spots<br />But smaller: more rapid repetition rate to achieve a g...
  1<br />  5<br />  3<br />  4<br />  2<br /><ul><li>Due to the high pulse frequency, there is a theoretical risk of therm...
ALLEGRETTO WAVE® Eye-Q laser prevents this by only allowing every fifth pulse to overlap with a previous one.
Optimal temporal and spacial shot distribution is required to minimize potential thermal load  </li></ul>Optimized shot di...
Eye tracking<br />Must have PRECISE eye tracking to follow eye during abaltion<br />Precision limited by LATENCY<br />Time...
Eye tracking is an integral feature that helps assure that each laser pulse is placed where planned1.<br /><ul><li>Natural...
The ALLEGRETTO WAVE® Eye-Q laser tracker can:
Center on natural pupils from 1.5 mm to 8 mm diameter
Track pupil movements at 400 Hz
Acquires the image, processes it and verifies the position of eye before releasing the pulse.</li></ul>The 400-Hz eye trac...
Wavefront Optimized<br />Designed to avoid induction of spherical aberration<br />Earlier lasers and techniques less predi...
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THE EVOLUTION OF LASIK by J. Alberto Martinez MD COPE ID 31538-RS

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Visionary Ophthalmology Lectures Series 12, May 22nd 2011

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THE EVOLUTION OF LASIK by J. Alberto Martinez MD COPE ID 31538-RS

  1. 1.
  2. 2. From freezing to photoablation<br />The evolution of lasik<br />J. Alberto Martinez, M.D.<br /> Visionary Ophthalmology<br />May 12, 2011<br />
  3. 3.
  4. 4. OUTLINE<br />Incisional refractive surgery<br />Lamellar refractive surgery<br />Non-excimer laser lamellar refractive surgery<br />Excimer assisted lamellar refractive surgery<br />LASIK in the US<br />Femptosecond role in LASIK<br />Future of Refractive surgery<br />
  5. 5. Martinez’ classification of refractive surgery<br />Corneal procedures<br />Conjuntival procedures<br />Scleral procedures<br />Anterior chamber procedures<br />Iris/pupil procedures?<br />Sulcus procedures<br />Crystalline lens procedures<br />Globe shortening procedures<br />
  6. 6. Corneal procedures<br />Incisional procedures: RK, AK, LRI<br />Surface reshaping: PRK ( PTK), CK orthokeratology<br />Stromal reshaping: LASIK, Intralasestromal ablation<br />Augmentation procedures: Corneal inlays, Intacts<br />
  7. 7. Radial Keratotomy<br />Tsutomu Sato of Japan, 1933: 40-45 endothelial side cuts: Corneal edema<br />
  8. 8. Cornea: RK, AK/LRI <br />RK reshapes the cornea by relaxing steep meridians<br />Advantages: Quick, inexpensive<br />Disadvantages: Inaccurate, variable <br />
  9. 9. Radial Keratotomy<br />Early 1970s, Dr. Yenaliev,<br />Durnev and Fyodorov: External<br /> incisions only<br />Dr Fyodorov And Dr. Leo Boris introduced RK in the United States in 1978<br />Incisional refractive surgery still plays a role in some procedures, mostly LRI’s or limbal relaxing incisions for astigmatic correction after cataract surgery<br />
  10. 10. Incisional refractive surgery (IRS)<br />Outdated because:<br />Unpredictability<br />Limited range of effect (minor myopia, up to four diopters)<br />Better options (lamellar)<br />Still however used today as LRI, limbal relaxing incisions for multifocal IOLs<br />
  11. 11. Dr. Luis Ruiz, RK innovator<br />
  12. 12. CK®<br />Thermokeratoplasty: technique that uses RF energy to heat and reshape the cornea<br />
  13. 13. Lamellar Refractive surgery<br />Conceived and developed By <br />Dr. Jose Barraquer<br />Bogota, Colombia.<br />Voted as the most influential ophthalmologist of the 20th century<br />
  14. 14. Ley de Espesores – Law of Thicknes<br />
  15. 15. Keratomilieusis<br />
  16. 16. The Microkeratome<br />
  17. 17. Automated Lamellar Keratoplasty, ALK<br />
  18. 18. ExcimerLaser <br />Developed at IBM in 1976 to etch microchips<br />First introduced by Stephen Trokel in 1983 <br />LASIK was essentially a procedure already performed in Bogota<br /> by Dr. Barraquer.<br />Excimerlaser only<br /> made it more accurate<br />
  19. 19. EXCIMER LASER<br />
  20. 20. Excimer Laser in ALK<br />1990 LASIK was born as the “flap and Zap” Dr. Steven Slade <br />1995 LASIK approved by the FDA for commercial use<br />1999 use of wavefront technology<br />2008 LASIK approved for Navy Pilots and astronauts<br />
  21. 21. ALK + Excimer = LASIK<br />
  22. 22. First Generation Excimer lasers<br />
  23. 23. Second Generation Excimer Lasers<br />
  24. 24. Wavescan: Wavefront scan<br />
  25. 25. Customized Ablations<br />
  26. 26. WAVEFRONT GUIDED VS.WAVEFRONT OPTIMIZED<br />
  27. 27. WavefrontGUIDEDTreatment<br />Wavefront measurement ( lower order aberrations: <br />Defocus (sphere) and Astigmatism (cylinder)<br />To measure Higher order aberrrations<br />Need Dilated pupils ( correspond to 6-7mmOZ)<br />
  28. 28. WavefrontGUIDEDTreatment<br />A wavefrontrefration with small pupils<br />Plus larger diameter treatments=<br />High technology autorefractionfollowed by standard excimer laser treatment<br />Optical aberrations increase with age, mostly associated with lenticular changes, thus not stable over time.<br />
  29. 29. Wavefront Optimized excimerlasers: Latest generation of lasers<br />ALLEGRETTO WAVE® LASER FEATURES<br />
  30. 30. Wavefront Optimized<br />Latest lasers: Smaller scanning spots<br />But smaller: more rapid repetition rate to achieve a given amount of tissue removal<br />Increased rate of laser firing causes higher temperature at treatment site.<br />
  31. 31. 1<br /> 5<br /> 3<br /> 4<br /> 2<br /><ul><li>Due to the high pulse frequency, there is a theoretical risk of thermal effects1.
  32. 32. ALLEGRETTO WAVE® Eye-Q laser prevents this by only allowing every fifth pulse to overlap with a previous one.
  33. 33. Optimal temporal and spacial shot distribution is required to minimize potential thermal load </li></ul>Optimized shot distribution ensure that only every 5th pulse is allowed to overlap the first. This helps minimize thermal build up and provides adequate time for plume evacuation.<br />1. Mrochen M et al. J Cataract Refract Surg. 2009;35:363-373.<br />Thermal Optimized Shot Distribution<br />
  34. 34. Eye tracking<br />Must have PRECISE eye tracking to follow eye during abaltion<br />Precision limited by LATENCY<br />Time between eye recognition of movement and redirection of scanning spot<br />With smaller spots LATENCY must be minimized<br />
  35. 35. Eye tracking is an integral feature that helps assure that each laser pulse is placed where planned1.<br /><ul><li>Natural eye movements range from 20 Hz to 60 Hz
  36. 36. The ALLEGRETTO WAVE® Eye-Q laser tracker can:
  37. 37. Center on natural pupils from 1.5 mm to 8 mm diameter
  38. 38. Track pupil movements at 400 Hz
  39. 39. Acquires the image, processes it and verifies the position of eye before releasing the pulse.</li></ul>The 400-Hz eye tracking system verifies the eye position and automatically corrects shot placement for natural eye movement.<br />1. Chalita MR, Krueger RR. In: Albert & Jakobiec’s Principles and Practices in Ophthalmology. 3rd ed. Philadelphia, PA: Saunders W B Co; 2008:1041-1049.<br />Active, High-speed Eye Tracking<br />
  40. 40. Wavefront Optimized<br />Designed to avoid induction of spherical aberration<br />Earlier lasers and techniques less predictable with spherical aberration<br />Goal is to reshape cornea to a theoretically superior profile<br />Translate clinical data to precise tissue removal<br />
  41. 41. Peripheral Pulse Control<br />To compensate for energy loss in the cornea periphery, the number of laser shots are increased<br />Energy loss is attributed to1:<br /><ul><li>The cosine effect and beam ovalization which decrease energy
  42. 42. The angle of incidence approaches the critical angle in the periphery and becomes partially absorbed
  43. 43. The result is less fluence and thus sub-optimal ablation</li></ul>Normal Ablation<br />When beam shape broadens in the periphery, fluency can fall below the ablation threshold (≈45 uJ/cm2). <br />Wavefront Optimized® algorithms maintain the natural pre-op corneal curvature by compensating for this effect. The algorithm delivers more shots to the periphery, to produce a refractive treatment with minimal increases in spherical aberration.<br />1. Seiler T, Koller T. In: Albert & Jakobiec’s Principles and Practices in Ophthalmology. 3rd ed. Philadelphia, PA: Saunders W B Co; 2008:981-985.<br />
  44. 44. The Femtosecond laser<br />
  45. 45. Corneal reshaping: Intralase<br />PresbyLASIK: Ablation within the stroma without disrupting the surface. Great promise . Developed by Dr. Luis A. Ruiz of Bogota, Colombia<br />
  46. 46.
  47. 47. IDEAL IOL<br />
  48. 48. Thank you for your attention!<br />Contact information:<br />J. Alberto Martinez MD<br />www.myeyesurgeon.com<br />jalbertom@comcast.net<br />

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