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a new option for keratoconus

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a new option for keratoconus

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    1. A New Option for Keratoconus

    7. History

    8. 1978 A.E. Reynolds, O.D. conceives of Intrastromal Corneal Ring (ICR) 1985 - First pre-clinical studies on Dr. Reynolds' product 1991 - First human clinical trials begun - Brazil 1996 - U.S. myopia clinical trial begun, 150 ICR - CE Mark approval of ICR in Europe, -1.00 to -4.50 D 1997 - Joseph Colin, MD inserts first ICR for Keratoconus Milestones

    9. INTACS Design Features Precision manufactured to 0.01mm: 150 arcs PMMA Unique hexagonal cross-section design with 7mm wide optical zone Positioning holes for manipulation Inserts placement: In peripheral cornea Between stromal layers Slide 11 The INTACS design that is approved for the correction of low myopia in Europe and in the United States consists of two 150 degree arcs of PMMA that are lathe cut to specified thicknesses. The inner diameter of the INTACS is 6.8 mm and the outer diameter is 8.1 mm. The INTACS are normally positioned at 2/3 depth, centered on the geometric corneal center, and they are normally oriented in a vertical pattern as demonstrated in this slide.Slide 11 The INTACS design that is approved for the correction of low myopia in Europe and in the United States consists of two 150 degree arcs of PMMA that are lathe cut to specified thicknesses. The inner diameter of the INTACS is 6.8 mm and the outer diameter is 8.1 mm. The INTACS are normally positioned at 2/3 depth, centered on the geometric corneal center, and they are normally oriented in a vertical pattern as demonstrated in this slide.

    11. 1999 - FDA approval for myopia, -1.00 to -3.00 D 2001 - Addition Technology purchased INTACS technology to pursue keratoconus indication 2003 - CE approval granted for keratoconus in Europe 2004 - FDA approval for keratoconus under Humanitarian Device Exemption (HDE) 2005 Over 5000 INTACS corneal implants procedures for keratoconus performed worldwide Milestones contd

    12. Keratoconus Non-Inflammatory Ectasia Stromal Thinning Disruption of Bowmans Membrane Corneal Ectasia Myopia Irregular Astigmatism Optical Correction Spectacles early Contact Lenses later Slide 3 Keratoconus is a non-inflammatory, progressive ectatic corneal disorder associated with stromal thinning and disruption of Bowmans membrane. The ectatic cornea causes a myopic refractive error and marked irregular astigmatism which grows worse as the disorder progresses. In early stages of the disorder, patients may be corrected with spectacles, but with moderate disease optical correction often can only be achieved with contact lenses, and in severe cases, when contact lens correction no longer provides good vision, surgery may be necessary.Slide 3 Keratoconus is a non-inflammatory, progressive ectatic corneal disorder associated with stromal thinning and disruption of Bowmans membrane. The ectatic cornea causes a myopic refractive error and marked irregular astigmatism which grows worse as the disorder progresses. In early stages of the disorder, patients may be corrected with spectacles, but with moderate disease optical correction often can only be achieved with contact lenses, and in severe cases, when contact lens correction no longer provides good vision, surgery may be necessary.

    13. Keratoconus Demographics Estimates vary from 50 to 170 per 100,000 Obscure Etiology Heredity Allergies, Eye Rubbing Slide 4 Previously the prevalence of Keratoconus was estimated at between 50 and 170 per 100,000 people. Over the last 10 to 15 years, however, the work of Rabinowitz and others have identified a high incidence of topographic forme fruste or pre-Keratoconus and current estimates have increased to between 0.5 to 1.7 per 1000. While in some cases there may a distinct hereditary pattern, or an association with allergy or eye rubbing, at the present time the etiology of this disorder remains obscure.Slide 4 Previously the prevalence of Keratoconus was estimated at between 50 and 170 per 100,000 people. Over the last 10 to 15 years, however, the work of Rabinowitz and others have identified a high incidence of topographic forme fruste or pre-Keratoconus and current estimates have increased to between 0.5 to 1.7 per 1000. While in some cases there may a distinct hereditary pattern, or an association with allergy or eye rubbing, at the present time the etiology of this disorder remains obscure.

    14. Why Does the Cornea Bulge in Keratoconus? Corneal tissue is abnormal Too elastic? Abnormal cross-linking of collagen? Loss of structural integrity of Bowmans Layer? Keratocyte apoptosis Trauma (eye rubbing) Corneal tissue bulges because it is too thin? Slide 5 A key question, is why does the cornea bulge in Keratoconus? Various studies have identified increased elasticity possibly due to abnormal cross-linking of collagen as well as variations in the collagen and proteoglycan makeup of the Keratoconic cornea. Recently, Wilson and others have advanced the hypothesis that interleukins produced by the epithelium in the presence of eye rubbing or allergy may initiate an apoptosis cascade leading to the keratocytes death and eventual tissue thinning. Whether the cornea bulges because it is too elastic or too thin is not known, but the association of thinning and bulging is clear in most cases.Slide 5 A key question, is why does the cornea bulge in Keratoconus? Various studies have identified increased elasticity possibly due to abnormal cross-linking of collagen as well as variations in the collagen and proteoglycan makeup of the Keratoconic cornea. Recently, Wilson and others have advanced the hypothesis that interleukins produced by the epithelium in the presence of eye rubbing or allergy may initiate an apoptosis cascade leading to the keratocytes death and eventual tissue thinning. Whether the cornea bulges because it is too elastic or too thin is not known, but the association of thinning and bulging is clear in most cases.

    15. Current Surgical Options - Keratoconus 10% to 20% of Keratoconus Patients Ultimately Require Surgery Lamellar Keratoplasty Interface haze limits visual result Penetrating Keratoplasty Most frequent procedure 4,771 cases in 2004 (US) 80-90% successful Issues Graft rejection rate 17.9% Continued astigmatism Endothelial cell loss (limited longevity of graft) Recurrence of Keratoconus Slide 7 Rabinowitz estimates that between 10 and 20% of Keratoconus patients will ultimately undergo a corneal transplant. Because of the technical difficulty of freehand lamellar keratoplasty and the limitation of visual correction due to interface opacity, most patients undergo Penetrating Keratoplasty. In 2002, according to EBAA statistics there were 4813 corneal transplants performed for Keratoconus. Although PK is successful 80 to 90% of the time, there are issues including an estimated 17.9% rejection rate, continued astigmatism, progressive endothelial cell loss limiting the longevity of the graft, and recurrence of Keratoconus in the graft. Certainly there is room for new approaches and this is where the additive corneal procedures come in.Slide 7 Rabinowitz estimates that between 10 and 20% of Keratoconus patients will ultimately undergo a corneal transplant. Because of the technical difficulty of freehand lamellar keratoplasty and the limitation of visual correction due to interface opacity, most patients undergo Penetrating Keratoplasty. In 2002, according to EBAA statistics there were 4813 corneal transplants performed for Keratoconus. Although PK is successful 80 to 90% of the time, there are issues including an estimated 17.9% rejection rate, continued astigmatism, progressive endothelial cell loss limiting the longevity of the graft, and recurrence of Keratoconus in the graft. Certainly there is room for new approaches and this is where the additive corneal procedures come in.

    16. INTACS a New Surgical Option Goal is to restore functional vision Effective functional refraction with soft, soft-toric, or rigid contact lenses Create cornea more receptive to contact lenses

    17. Watch the Pre-op and Post-op mire INTACS Normalize Corneal Shape

    18. Pre-Op UCVA 20/200 MR: -4.75 + 5.25 X 005 = 20/40 RGP intolerant

    19. Fitting CLs on keratoconus patients who have INTACS is feasible and has a role in augmenting their vision Nepomuceno, Boxer Wachler, Weissman, CLAE 2003 175-180 pre-op BCVA post-op BCVA post-op BCLVA Lens 31 F 20/32 20/25 20/16 soft toric 44 M 20/125 20/50 20/25 cust. RGP 34 M 20/63 20/40 20/20 cust. RGP All were CF UCVA pre-op and 20/200 or better post-op

    20. INTACS Case Files

    21. INTACS Case Files

    24. INTACS Case Files

    25. INTACS Case Files

    26. INTACS Optics Maintains prolate cornea Enhances structural integrity (second limbus) Additive Removable - Replaceable Large, clear central optical zone

    27. INTACS & The Prolate Cornea The smooth, prolate corneal shape provided by the Intacs has superior wavefront properties measured both on the corneal surface and through- the- eye, using interferometric and Hartmann- Schack wavefront sensing techniques. The wavefront difference between Intacs and tissue removal techniques can be seen in this slide which shows the wavefront difference at the corneal surface (sombrero hat vs doughnut) and through- the- eye ( regular dot grid vs pinched dot grid). The more regular grid pattern for Intacs implies that a better wavefront and therefore a better image is being delivered to the retina using Intacs. This is, in part, due to the smooth, prolate corneal surface provided by Intacs as opposed to the oblate surface created by tissue removal from the center of the cornea using other refractive techniques. The smooth, prolate corneal shape provided by the Intacs has superior wavefront properties measured both on the corneal surface and through- the- eye, using interferometric and Hartmann- Schack wavefront sensing techniques.

    28. Peer Reviewed Literature INTACS for Keratoconus

    29. INTACS Clinical Overview First case 1997: Joseph Colin, MD Decentered Cone Segment Placement Superior thin segment : 0.25 mm Inferior thick segment : 0.45 mm Very encouraging results Patient scheduled for immediate PKP, Transplant has been deferred 7+ years with acceptable BSCVA Reduction in myopia and astigmatism Results stable over time Slide 12 Early on, Joseph Colin, then from Brest, France, was intrigued with using INTACS not just so much for the treatment of myopia but rather more for Keratoconus. In June 1997, Colin was the first surgeon to implant INTACS for Keratoconus. His technique used a temporal incision through which he implanted a superior, thin INTACS segment 0.25 mm thick to flatten the cone, and a thicker, inferior INTACS segment 0.45 mm thick to lift the cone. Slide 12 Early on, Joseph Colin, then from Brest, France, was intrigued with using INTACS not just so much for the treatment of myopia but rather more for Keratoconus. In June 1997, Colin was the first surgeon to implant INTACS for Keratoconus. His technique used a temporal incision through which he implanted a superior, thin INTACS segment 0.25 mm thick to flatten the cone, and a thicker, inferior INTACS segment 0.45 mm thick to lift the cone.

    30. Combined Studies 1997- 2003 Colin (2001) 10 eyes Ophthalmology 2001; 108:1409-1414. Siganos (2003) 33 eyes American Journal of Ophthalmology 2003; 135:1:64-70. Boxer-Wachler (2003) 74 Eyes Ophthalmology. 2003; 110:1031-1040. European Clinical (2003) 34 eyes Accepted for Publication Ophthalmology Slide 15 The experience with INTACS for Keratoconus is increasing world wide. Nonetheless, the number of peer reviewed publications with extended follow-up is limited. For todays presentation, I will combine the published studies of Colin, Siganos, and Boxer Wachler, as well as the unpublished data from the European Keratoconus clinical trial, all of which have at least one year follow up. These combined studies include a total experience of 166 treated Keratoconic eyes.Slide 15 The experience with INTACS for Keratoconus is increasing world wide. Nonetheless, the number of peer reviewed publications with extended follow-up is limited. For todays presentation, I will combine the published studies of Colin, Siganos, and Boxer Wachler, as well as the unpublished data from the European Keratoconus clinical trial, all of which have at least one year follow up. These combined studies include a total experience of 166 treated Keratoconic eyes.

    33. Combined Studies 1997 - 2003 Follow-up shows stable and lasting effect Very Few Surgical Complications Observed Postoperative Complications Superficial placement Segment migration Visual symptoms Lack of effect Manageable with INTACS Removal 14/174 eyes (8%) Majority of patients returned to preoperative refraction upon removal Several have gone on to have successful corneal transplantation Slide 24 There were a fewcomplications in this series of patients. They included - patient dissatisfaction, lack of effect, segment migration, and corneal erosion when the INTACS were placed superficially. All of these complications were manageable by INTACS removal. In this series, the overall complication rate appears to be 14 out of 165 eyes or 8.5% and several of these patients went on to have successful corneal transplants without difficulty.Slide 24 There were a fewcomplications in this series of patients. They included - patient dissatisfaction, lack of effect, segment migration, and corneal erosion when the INTACS were placed superficially. All of these complications were manageable by INTACS removal. In this series, the overall complication rate appears to be 14 out of 165 eyes or 8.5% and several of these patients went on to have successful corneal transplants without difficulty.

    34. European Keratoconus Study Results Summary Dr. Joseph Colin (France) pioneered the use of INTACS in Keratoconus First case in 1997 7 years follow up with stable results Very few INTACS patients have required corneal transplants in 7 years In the few cases where PKP was performed, no problems were reported

    35. European Keratoconus Study Slide 20 The patients in the European study had a mean myopic decrease of 3.1 diopters and a mean cylinder decrease of 2.94 diopters. As expected, Boxer Wachlers results showed slightly less myopic decrease due to the thinner INTACS used. Stability of the post op refractions was achieved between three and six months in the European study.Slide 20 The patients in the European study had a mean myopic decrease of 3.1 diopters and a mean cylinder decrease of 2.94 diopters. As expected, Boxer Wachlers results showed slightly less myopic decrease due to the thinner INTACS used. Stability of the post op refractions was achieved between three and six months in the European study.

    36. European Keratoconus Study2 year data - Joseph Colin, MD* 96 of 100 eyes, initially referred for PKP, successfully implanted with INTACS and remain stable after 24 months 100% became contact lens tolerant, some patients became correctable with spectacles and a subset required no correction 80% have improved UCVA and 68% improved BCVA at year 2 Manifest refraction, cylinder, MRSE and pachymetry continued to improve at year 2 over year 1 and preoperative exams

    38. INTACS - PKP Comparison PKP Irreversible Procedure Time: 1 Hour Rehab Time: 12-18 Months Intraocular Procedure Lifetime Follow-up required Complications Cataract Glaucoma Endophthalmitis Rejection Expulsive hemorrhage Corneal ulcer Neovascularization Induced astigmatism Disease recurrence Risk of viral transference A head to head comparison of keratoplasty and Intacs shows that the major advantages of Intacs are the rehabilitation time (several weeks as opposed to several months). A head to head comparison of keratoplasty and Intacs shows that the major advantages of Intacs are the rehabilitation time (several weeks as opposed to several months).

    39. INTACS - PKP Comparison PKP A head to head comparison of keratoplasty and Intacs shows that the major advantages of Intacs are the rehabilitation time (several weeks as opposed to several months). A head to head comparison of keratoplasty and Intacs shows that the major advantages of Intacs are the rehabilitation time (several weeks as opposed to several months).

    40. Conclusions: INTACS Intervention is Superior to Transplant Goal of INTACS is to restore functional vision Effective functional refraction with soft, soft-toric, or rigid contact lenses is likely Creates cornea more receptive to contact lenses INTACS implantation reduces corneal coning Central cone is flattened Asymmetrical cones are repositioned centrally Post-surgical recovery Visual improvement can be immediate Vision stabilizes in months rather than a year or longer High potential to defer transplant

    41. INTACS Case Files

    42. INTACS Case Files

    43. INTACS Removal & Replacement Summary Easy to remove In FDA study, no complications post-removal Preliminary data indicates that the patients return to their preoperative refractive error in most cases Patients are able to return to their original mode of correction or to pursue an alternative refractive procedure

    46. Contact lens intolerant keratoconus Improve contact lens success, UCVA, BCVA Defer PKP and associated risks Keep on the conservative side of leading edge patient care technology Retain patient loyalty and follow-up care Why recommend INTACS ?

    47. Ideal INTACS Patients

    48. INTACS a refractive option for

    49. Thank you !

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