MYOPIA AND NUTRITION Myopia epidemic Myopia is extremely ...
High Myopia Final CZM Dubai 2011
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Transcript of High Myopia Final CZM Dubai 2011
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Very high myopic LASIK using newhybrid aspheric profiles
Dan Z Reinstein MD MA(Cantab) FRCSC FRCOphth1,2,3,4
1. London Vision Clinic, London, UK
2. St. Thomas Hospital - Kings College, London, UK
3. Weill Medical College of Cornell University, New York, USA
4. Centre Hospitalier National dOphtalmologie, (Pr. Laroche) , Paris, France
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DZ Reinstein [email protected]
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. O'Brart
DP, Lohmann CP, Fitzke FW, Smith SE, Kerr-Muir MG, Marshall J.
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DZ Reinstein [email protected]
Ablation Profile Design: Larger Optical Zone
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. O'Brart DP, Corbett MC, Lohmann CP,
Kerr Muir MG, Marshall J.
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.
O'Brart DP, Gartry DS, Lohmann CP, Muir MG, Marshall J.
Topography Wavefront
Z(4,0) (OSA)
1.18 m
Example: 5-mm Munnerlyn ablation for -6.00 D (1993 Summit Laser)
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DZ Reinstein [email protected]
Ablation Profile Design: Aspheric Profiles
Barraquer 1980 Suggested parabolic keratomileusis
Seiler 1993 PRK aspheric profiles Less starburst & halos
Larger effective clear optical zone size
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Why was spherical aberrationincreasing?
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Fluence correction: Topography
Beam reflection compensation Beam projection compensation
Optimization: Fluence correction
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.
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Optimization
Biomechanics
VHF digital ultrasound
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Artemis C12 DisplayReinstein et al. Journal of Refractive Surgery
2000 Jul-Aug;16:414-30
Roberts C. The cornea is not a piece of plastic.
JRS 2000; 16:407-413
VHF digital ultrasound
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Examples of Peripheral Stromal Thickening
Roberts C. The cornea is not a piece of plastic.
Peripheral Stromal
Thickening
Central Flattening
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DZ Reinstein [email protected]
Corneal Biomechanical Trade-off
Hyperopic shift induced by
Central flattening due to peripheral tissue removal
Myopic shift induced by
Epithelial thickening
Bowing of the back surface
Post-Op
Pre-Op
Back surface bowing
Epithelial thickening
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Free lunch?
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DZ Reinstein [email protected]
ESCRS 2002, DZ Reinstein: Z4,0-Slider(aka Q-slider)
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DZ Reinstein [email protected]
ESCRS 2002, DZ Reinstein: Z4,0-Slider(aka Q-slider)
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DZ Reinstein [email protected]
ESCRS 2002, DZ Reinstein: Z4,0-Slider(aka Q-slider)
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DZ Reinstein [email protected]
ESCRS 2002, DZ Reinstein: Z4,0-Slider(aka Q-slider)
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DZ Reinstein [email protected]
ESCRS 2002, DZ Reinstein: Z4,0-Slider(aka Q-slider)
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DZ Reinstein [email protected]
ESCRS 2002, DZ Reinstein: Z4,0-Slider(aka Q-slider)
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DZ Reinstein [email protected]
Free Lunch?
Increasing ablation zone diameter
Adding asphericity
Increases central
ablation depth
No Free Lunch
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550 m Pachymetry: Forces Compromise
Modern asphericablation profiles still induce spherical
aberration Problem: high myopic corrections may result in NVDs
y = -0.059x - 0.0136
R= 0.6444
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
-10.00-9.00-8.00-7.00-6.00-5.00-4.00-3.00-2.00-1.000.00
Attempted Spherical Equivalent vs. Change in Z(4,0) Coefficient
ASA Treatments
Attempted Spherical Equivalent (Diopters)
Changein
Z(4,0)Coefficient(m,OSA)
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Wavefront-Guided Treatmentof Spherical Aberration
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Contro l Pre Control PostPre CRS-M
RepairPost CRSM-
Repair
Sph Ab Area 122 276 563 410
0
100
200
300
400
500
600
700800
900
m
2
3 cpd 6 cpd 12 cpd 18 cpd
Control Pre 1.02 1.02 1.03 1.04
Control Post 1.04 1.01 1.03 1.01Pre CRSM-Repair 0.85 0.84 0.77 0.75
Post CRSM-Repair 1.04 1.02 1.02 1.00
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
NormalizedContrast
SensitivityRatio
Correlation of Contrast with Wavefront
Spherical Aberration Contrast Sensitivity
27% Gross Reduction
53% NetReduction (cf tolerable level)
Tolerable level ~0.56 m @ 6mm
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DZ Reinstein [email protected]
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
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Patient 1, OD
-7.13 D Corrected
6mm OSA
Coma 0.04 m
Sph Ab 0.42 m
HO RMS 0.52 m
6mm OSA
Coma 0.09 m
Sph Ab 0.48 m
HO RMS 0.59 m
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DZ Reinstein [email protected]
Patient 1, Night Vision
Rx TreatedOD -6.50 -1.25 x 178
OS -8.25 -1.50 x 17
Pre Op Post Op
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Induction of Spherical Aberration
Complaint of NVD post RS1
1
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Limits to SA Pre-Compensation
Excess spherical aberration pre-compensation can
lead to central islands
TMS WASCA (zonal) Epithelium
OD
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CENTRAL ISLANDS:
Slides courtesy Gordon Balazsi, MD
-5.50 D ablationDiplopia first week
Slow resolution over 2 weeks
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CENTRAL ISLANDS:
Slides courtesy Gordon Balazsi, MD
-5.00 D ablation
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Ablation Depth with SA Pre-Compensation
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New Profile for High Myopia
Non-linear aspheric ablation profile:
Increasedperipheralablation (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
Roberts C. The cornea is not a piece of plastic.
Peripheral Stromal
Thickening
Central Flattening
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DZ Reinstein [email protected]
New Profile: Free Lunch
Over-corrected by +0.50 D compared with theory
Ablation depth lower than expected
y = 0.9958x - 0.5106
R = 0.9291
-14
-13
-12
-11
-10
-9
-8
-7
-6
-5
-14-13-12-11-10-9-8-7-6
Attempted vs. Achieved Spherical Equivalent
Attempted Spherical Equivalent (Diopters)
AchievedSphericalEquivalent(D
iopters)
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Ablation Depth for New Profile
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Femtosecond Lasers
Femtosecond lasers have improved flap thickness
reproducibility(VisuMax SD: 8 m) We can create thinner flaps (VisuMax: 80 m)
Thinner flaps extends the range of myopia in LASIK
Pre-release online
S
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Example RST Planning
Refraction -10.75 D sph
Pachymetry 509 m
Flap Thickness (VisuMax) 80 m
Ablation Depth 135 m
Predicted RST 296 m
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Outcomes
N P fil f Hi h M i
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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%
Ad t f T St P d
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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
T h G id d R t t t
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Topography Guided Retreatment
Pre Post Reduced
Sph Ab 0.48 m 0.28 m 41%
HO RMS 0.72 m 0.57 m 21%
MEL80 Hi h M i A
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MEL80 High Myopia: Accuracy
y = 1.0726x + 0.8394R = 0.8759
-14
-13
-12
-11
-10
-9
-8
-7
-14-13-12-11-10-9-8-7
Attempted vs. Achieved Spherical Equivalent
Attempted Spherical Equivalent (Diopters)
Ach
ievedSphericalEqu
ivalent(Diopters)
MEL80 Hi h M i A
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-2.00
To -1.51
-1.50
To -1.01
-1.00
To -0.51
-0.50
To -0.14
-0.13
To0.13
0.14
To+0.50
+0.51
To+1.00
+1.01
To+1.50
+1.51
To+2.00
Accuracy 0% 3% 15% 33% 25% 13% 7% 1% 1%
0%
3%
15%
33%
25%
13%
7%
1%1%0%
5%
10%
15%
20%
25%
30%
35%
PercentageEyes
Accuracy of Spherical Equivalent
Accuracy: Within Range of Intended
MEL80 High Myopia: Accuracy
Within0.50
D71%
Within1.00
D94%
Monocular Efficacy
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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%
1%
28%
83%
100%
11%
47%
90%
97% 99% 99% 99%
0%
20%
40%
60%
80%
100%
Percentage
Eyes
Monocular UCVA
Efficacy: Monocular UCVA
Monocular Efficacy(excluding eyes not intended plano)
n=176
MEL80 Hi h M i S f t BSCVA
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MEL80 High Myopia: Safety BSCVA
Loss 3 or
More
Loss 2 Loss 1No
Change
Gain 1Gain 2 or
MoreSafety 0.0% 0.0% 2% 40% 52% 6%
0.0% 0.0%2%
40%
52%
6%
0%
20%
40%
60%
PercentageEyes
Lines Change BSCVA
Safety: Lines Change BSCVA
N=4
n=220
MEL80 Hi h M i C t t S iti it
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MEL80 High Myopia: Contrast Sensitivity
*
* Statistically significant (p
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Thank You
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Very high myopic LASIK using new
hybrid aspheric profilesDan Z Reinstein MD MA(Cantab) FRCSC FRCOphth1,2,3,4
Thank You