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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, 150ş 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 cont’d
12. Keratoconus Non-Inflammatory Ectasia
Stromal Thinning
Disruption of Bowman’s 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 Bowman’s 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 Bowman’s 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 Bowman’s 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 CL’s 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 today’s 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 today’s 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 Wachler’s 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 Wachler’s 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 !