Latest Developments in Cataract Surgery

New Technologies In Surgery
Michael L. Nordlund, MD,PhD
Vice Chairman
Cincinnati Eye Institute
Technologies
• Intacs
• Collagen X-linking
• Femtosecond laser &
cataract surgery
Keratoconus
• Non-Inflammatory Corneal
Ectasia
• Stromal Thinning
• Corneal Steepening
• Myopia
• Irregular Astigmatism
Keratoconus
• Demographics
• Estimates vary from 50 to 170 per
100,000 population
!
• Obscure Etiology
• Heredity
• Eye Rubbing
• Allergies, down syndrome, atopy
Histology in Keratoconus
• Epithelial thinning
• Loss of integrity of
Bowman’s Layer
• Keratocyte loss
• Stromal thinning
• Descemet’s breaks
Historical Treatment of Keratoconus
Optical
Spectacles
CL
Specialty CL
Therapeutic
Lamellar kertaoplasty
Penetrating keratoplasty
Keratoconus Surgery
• Lamellar Keratoplasty
•
Interface haze limits visual result
• Penetrating Keratoplasty
•
•
•
Most frequent in US 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
Alternative Treatments of Keratoconus
• INTACs
• Collagen X-linking
• Deep Anterior Lamellar Keratoplasty
INTACS …a new Surgical Option
INTACS Design Features
• Precision lathe-cut to ± 0.01mm
•
•
150° arcs PMMA
Hexagonal-shaped section of a cone
▪ R2 = 8.1 mm
▪ R1= 6.8 mm
•
Positioning holes for manipulation
!
• Inserts placed in the stromal layer of the
peripheral cornea
•
•
•
Result in a reshaping of corneal curvature
The corneal bulge flattens
Stromal Lamellae
Thicker inserts increase flattening
How INTACS Work…
Inserts placed at 75% corneal depth
▪
!
Inserts separate corneal lamellae
▪
!
Separation shortens corneal arc length
▪
!
Central cornea flattens
▪
!
▪ Increased flattening achieved with
Stromal Lamellae
thicker segments
INTACS Mechanics
INTACS for Keratoconus
UCVA CF
BCVA: 20/50
MR: -4.75 + 5.00 @ 20
Max K: 55.78 @ 90
Custom RGP Intolerant
UCVA 20/40
BCVA: 20/25
MR: -2.00
Max K: 51.69 @ 89
RGP Tolerant
Architecture Modification
Architecture Modification
Pentacam Images
INTACS Clinical Overview
• First case 1997: Joseph Colin, MD
• Temporal Approach
▪ Superior thin segment : 0.25 mm; Flattens the cone
▪ Inferior thick segment : 0.45 mm; Lifts the cone
• Very encouraging results
▪ Patient scheduled for immediate PKP,
has been deferred 7+ years with acceptable BSCVA (Best Spectacle▪ Transplant
Corrected Visual Acuity)
▪ Reduction in myopia and astigmatism
▪ Results stable over time
Combined Studies 1997 to 2001
Change UCVA
78%
67%
72%
33%
22%
19%
0%
European Study
Siganos
0%
9%
Boxer Wachler
Combined Studies 1997 to 2001
Change BCVA
62%
52% 51%
45% 45%
32%
6%
European Study
Siganos
3%
4%
Boxer Wachler
CL Intolerant - Pre-Op BCVA Achieved to Complete Exam
European Keratoconus Study
▪ Change in MRSE
• Mean 3.1 Diopters Corrected
• Range 1.6 to 8.7 Diopters
!
▪ Change in Cylinder
• Mean 2.9 Diopters Corrected
• Range 0 to 7.5 Diopters
!
▪ Stability of refraction achieved at 3 to 6 months
• 75% within ± 1 Diopter
•
50% within ± 0.5 Diopter
European Keratoconus Study
• 2 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
Complications - Combined Studies
• 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
INTACS – PKP Comparison
Transplant
Intacs
INTACS - PKP Comparison
INTACS
!
PKP
!
▪ Reversible Out-Patient Procedure
▪ Irreversible Procedure
▪ Time: 20-30 Minutes
▪ Time: 1 Hour
▪ Rehab Time: 1-2 Weeks
▪ Rehab Time: 12-18 Months
▪ Corneal Lamellar Procedure
▪ Intraocular Procedure
▪ Complications
▪ Complications
• Unsatisfactory ring placement
• Segment extrusion
• Infection
(All easily managed with segment removal)
•
Cataract, Glaucoma, Rejection
•
Endophthalmitis, Expulsive hemorrhage
•
Neovascularization, Astigmatism
•
Disease recurrence
•
Risk of viral transference
INTACS - PKP Comparison
PKP
INTACS
▪ Endothelial cell loss, not clinically
significant1
!
▪ Provides structural integrity, PKP still
an option without complication
!
▪ Outcomes: predictable, case dependent
!
!
1Two-Year
Endothelial Cell Assessment following INTACS implantation, Azar
et al, J Refract Surg. 2001 Sept-Oct!
▪ Significant loss of endothelial cells
!
▪ Permanently weakened cornea with
risk of additional trauma
!
▪ Outcomes: unpredictable, often
unstable
Conclusions: INTACS Intervention can be a
Viable Alternative to Transplant
• Goal of INTACS is to restore functional vision
• INTACS flatten cones
• Effective functional refraction with soft, soft-toric, or rigid contact lenses
• Asymmetrical cones are repositioned centrally
• INTACS reduce higher order aberrations
•
•
•
Visual improvement can be immediate
Vision stabilizes in months rather than a year or longer
Potential to defer transplant
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
The INTACS Procedure
Ideal INTACS Patients
!
Contact Lens Intolerant Keratoconus
▪ K readings 45 to 60
▪ Contact lenses not providing functional vision
▪ Outright failure
▪ Inability to achieve 20/40
▪ Desire to forestall central scarring
▪ Apprehensive of transplant
Collagen Cross-Linking
+
=
Collagen Cross-Linking
• Natural process
• May explain natural
progression arrest
• Accelerated by
– photoactive agentriboflavin
– Elevated UVA levels
Cross-Linking Benefits
• Arrested progression of ectasia
• Corneal sterilization
– Acanthamoeba
– Fungus
– Bacterial
Cross-Linking & Ectasia
• Siena study 2010
– 363 pts
– 48-60 months
– Mean reduction in K of 2 D
– Improved BCVA of 1.9 lines
– Improved UCVA of 2.7 lines
– Arrest of progression
Cross-Linking Risks
• Haze
• Delayed healing
• Loss of BCVA
• Endothelial damage (<400 microns)
Cross-Linking Indications
• Not FDA approved
• Arrest of ectasia
– KCN & PMD
– LVC induced
• Infectious keratitis
– Acanthamoeba
– Fungus
– Severe bacteria
Ideal Ectasia Patient for X-Linking
• Early in disease!!!
• Goal is to prevent progression to need for:
– PK/DALK
– Specialty CL
– RGP CL
Modern Keratoconus Management
• Early disease
– X-linking
– Glasses/SCL per pt choice
• Moderate disease (CL dependent +/-intolerance)
– X-linking +/- Intacs
– CL
• Advanced disease (CL dependent, intolerant, =/-scarring)
– Intacs
– DALK
Laser Cataract Surgery
Traditional Cataract Surgery
• Corneal and LRI incisions via hand-held blade
• Manually created capsulorrhexis via bent needle or
forceps
• Ultrasonic phacoemulsification for lens fragmentation and
aspiration
Limitations of Manual Cataract Surgery
• Limited reproducibility of
• incisions
• CCC shape
• CCC size
• Phaco power
• can cause corneal burn, corneal
endothelial cell loss(1,2)
• LRIs
1/23/14
1Pereira
2Park
!
et al. JCRS 2006 Oct;32(10):1661-6
et al. Ophthalmic Surg Lasers Imaging. 2010 Mar-Apr;41(2):236-41
!39
Cataract Refractive Outcomes < Half that of LASIK
• Astigmatism Correction
– Manual LRIs imprecise in shape, size, and depth
• Effective Lens Position
– Most important factor in achieving expected IOL power
– Consistent CCC necessary to bring refractive result within
0.25d
– Centered in visual axis and covering optic by 1mm for
360°
Hill WE. Does the Capsulorrhexis Affect Refractive Outcomes? In Chang D, editor: In
Chang D, editor: Cataract Surgery Today, Bryn Mawr Communications, Wayne,
Pennsylvania, 2009. p. 78.
!
1/23/14
Hill WE. Hitting Emmetropia. Chang D. (ed.) In: Mastering Refractive IOLs – the Art
and Science. Slack Incorporated, 2008.
!40
An Evolving Definition of Cataract
Average Age of US Cataract Patient is Declining
Today: earlier diagnosis & treatment before substantial vision loss
•
In 2011, almost 800,000 surgeries will be performed on patients 55-64 years old
!
!
•
New surgical approaches available to improve UCVA for many patients
•
Established LASIK market validates that patients will pay for surgically improved vision
Goals of Laser Refractive Cataract Surgery
Improve Every Procedure
• Reduce surgeon variability
• Monofocal, Presbyopia, Astigmatism
• Refractive Precision and Integration
!
!
! Key Step
! Incision
Corneal
!
Current Surgery
Underutilized
Not Optimized
Capsulorhexis
Variablewith
Sized,
New laser-based standard, synonymous
patient pay
Not Centered
LRI
Lens Fragmentation
Imprecise
Excessive Ultrasound Power
Refractive Impact
Safety Impact
Astigmatism
Infection
Variable IOL Position &
Effective Lens Power
Capsular Tears,
Posterior Capsule Opacification
Overcorrection, undercorrection, aberrations
Delayed visual recovery
Perforations
Loss of endothelial cells, Capsule
Rupture
1/23/14
!42
Image-Guided Femtosecond Laser
•
Integrated OCT or Scheimpflug scans entire anterior segment; projects images of cornea, lens, iris, capsule onto video microscope
•
Surgeon selects incisions and lens treatment; patterns are projected onto images and confirmed
•
Procedure time ~ 1 minute. Projects real-time images as lens is fragmented, capsulotomy is created and then all corneal incisions.
Femtosecond Laser Cataract Surgery
Primary Incisions
• Two and three plane incisions seal very well
• 2.4mm wide, 1.6 mm long
3 hours post-op 2.4mm laser incision
Arcuate Astigmatic Incisions
Precise depth, length, axis
3 hours post-op lri laser incision
Highly Reproducible Capsulotomy
Laser (n=60)
Manual (n=60)
!47
RESULTS – REDUCTION IN CDE
16.00
13.83
12.71
12.00
Lower
32%
CDE
11.52
Lower
42%
8.00
Lower
50%
LenSx
Manual
9.35
42%
6.67
6.51
6.41
5.47
4.00
0.00
All
Soft
Moderate
Dense
Cataract Grade
•
•
42% Reduction in CDE All Cataract Grades
32% Reduction in CDE Dense Cataracts
!48
Laser Cataract Surgery Conclusions
!
• Theoretically the precision of the laser should make cataract
outcomes better and safer.
• In practice, improvements in safety or vision have NOT been
demonstrated.
• Despite precision of the laser, there remain many other significant
variables in cataract surgery.
• It does markedly increase the cost per case and increase length of
case.
• Patients and industry will likely continue the expansion of its use.
• Time will tell if the laser will result in better outcomes or just more
expensive surgery.
Conclusions
• Technological advances:
– are changing the way we manage patients
– offering patients improved outcomes
– driving cost increases in medicine
!
!