integration of aberrometry and topography with the i trace system
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Integration of Aberrometry Integration of Aberrometry and Topography with theand Topography with the
i i Trace SystemTrace System
July 2005July 2005
Joe S. Wakil, MD - Joe S. Wakil, MD -
Tracey Technologies, LLCTracey Technologies, LLC
EyeSys Vision, Inc.EyeSys Vision, Inc.
Founding Technology Founding Technology Developers:Developers:
Vasyl Molebny, DScVasyl Molebny, DSc
Kiev, UkraineKiev, Ukraine
Ioannis Pallikaris, MDIoannis Pallikaris, MD
Crete, GreeceCrete, Greece
Canadian & Swedish GovernmentsCanadian & Swedish Governments
Why Aberroscopy?Why Aberroscopy?
Current Laser Technology Permits One to Current Laser Technology Permits One to Go Beyond Correction of Sphere and Go Beyond Correction of Sphere and
AstigmatismAstigmatism
You Can Now Address Your Patient’s You Can Now Address Your Patient’s Quality of VisionQuality of Vision
High Order Aberrations DefineHigh Order Aberrations Define Quality of VisionQuality of Vision
Why Ray Tracing?Why Ray Tracing?Because… the Eye is NOT a Telescope!Because… the Eye is NOT a Telescope!
Effects Refraction (ex. Night Myopia)Effects Refraction (ex. Night Myopia)Refraction is NOT a FIXED Number! Refraction is NOT a FIXED Number!
Effects Refraction (Instrument Myopia)Effects Refraction (Instrument Myopia)
Effects Quality of Vision (Aberrations) Effects Quality of Vision (Aberrations)
Where are the Sources of Where are the Sources of Aberrations? Aberrations?
How do they change with Surgery?How do they change with Surgery?Cornea:Cornea:
Lens:Lens:
Pupil Size:Pupil Size:
Accommodation:Accommodation:
Tear Film:Tear Film:
Astigmatism (Irreg.), Sph & other HOAAstigmatism (Irreg.), Sph & other HOA
Astigmatism, Coma & other HOAAstigmatism, Coma & other HOA
The Eye is NOT a TelescopeThe Eye is NOT a Telescope
EYEEYE• Off-Axis designOff-Axis design• No magnification No magnification • Variable apertureVariable aperture• Variable detector res.Variable detector res.• AccommodationAccommodation• Changing fixationChanging fixation• Brain image Brain image
processingprocessing• Nature-madeNature-made
TELESCOPETELESCOPE• On-Axis designOn-Axis design• High magnificationHigh magnification• Fixed apertureFixed aperture• Constant detector res.Constant detector res.• No accommodationNo accommodation• Fixed alignmentFixed alignment• Digital image Digital image
processingprocessing• Man-madeMan-made
Significant Higher Order AberrationsSignificant Higher Order Aberrations
Coma
Spherical Aberration
Trefoil
Aberrometer/Wavefront Aberrometer/Wavefront TechnologiesTechnologies
• Hartmann-Shack Lenslet ArrayHartmann-Shack Lenslet Array• Tscherning AberrometerTscherning Aberrometer• Differential SkiascopyDifferential Skiascopy
• Ray TracingRay TracingFeatures:Features:-Rapid, point by point, IR measurement - -Rapid, point by point, IR measurement -
no data confusionno data confusion
-Pupillometry with auto-tracking/capture -Pupillometry with auto-tracking/capture
-Programmable sampling (256 pts.) in any -Programmable sampling (256 pts.) in any pupil up to 8mmpupil up to 8mm
-Open Field Fixation – avoid instrument -Open Field Fixation – avoid instrument myopia and measure Accommodationmyopia and measure Accommodation
-Corneal Topography integration – -Corneal Topography integration –
able to measure Lens Aberrationsable to measure Lens Aberrations
Hartmann ShackHartmann Shack
Hartmann ShackHartmann Shack
Hartmann-ShackHartmann-ShackWavefront SensorWavefront Sensor
H/S Photo of patient with tight eye lid courtesy David WilliamsH/S Photo of patient with tight eye lid courtesy David Williams
TscherningTscherning
Disadvantages of H-S and Disadvantages of H-S and TscherningTscherning
• Measures All Points at Once - Measures All Points at Once - Data Confusion, Compromised ResolutionData Confusion, Compromised Resolution
• Limited Dynamic Range – Limited Dynamic Range – Cannot Cannot Measure Highly Irregular EyesMeasure Highly Irregular Eyes
• Highly Sensitive to Noise – Highly Sensitive to Noise – Slow, Requires Multiple ScansSlow, Requires Multiple Scans
• Expensive Components – Expensive Components – High Cost to Purchase and RepairHigh Cost to Purchase and Repair
• H-S Measures Reverse Aberrations – H-S Measures Reverse Aberrations – Not Physiologic with Real Vision especially Not Physiologic with Real Vision especially for for High Orders in AccomodationHigh Orders in Accomodation
• Tscherning Needs 2-D Imaging of Retina - Tscherning Needs 2-D Imaging of Retina - Additional noise and errorsAdditional noise and errors
Differential SkiascopyDifferential Skiascopy
Disadvantages of Differential Disadvantages of Differential SkiascopySkiascopy
• Does NOT Measure Skew Aberrations – Does NOT Measure Skew Aberrations – Inaccurate WaveFront especially for Inaccurate WaveFront especially for Trefoil, Trefoil, Quadrafoil, etc. Quadrafoil, etc.
• Measures Multiple Points at Once (slit) Measures Multiple Points at Once (slit) and only in Perpendicular Direction - and only in Perpendicular Direction - Limited WF measurement (axial bias)Limited WF measurement (axial bias)
• No Open Field Fixation – No Open Field Fixation – Problem of instrument myopia in young Problem of instrument myopia in young patientspatients
Total Ocular Aberrations
Total Ocular Aberrations
Internal Optics
Aberrations
Internal Optics
Aberrations
Corneal Aberrations
Corneal Aberrations
Total Ocular AberrationsTotal Ocular Aberrations
*Measuring Corneal Aberration*Measuring Corneal Aberration without Lens without Lens or Total Aberration is of Questionable Valueor Total Aberration is of Questionable Value
The The iiTraceTrace
Principles of TraceyPrinciples of Tracey
• Programmable thin beam ray tracing Programmable thin beam ray tracing measuring forward aberrations of the eyemeasuring forward aberrations of the eye
• Rapid sequential measurement of data Rapid sequential measurement of data points over entire entrance pupil (<50ms)points over entire entrance pupil (<50ms)
• Localization of each reflected retinal spotLocalization of each reflected retinal spot• Integration of individual retinal spots to Integration of individual retinal spots to
form Point Spread Function (PSF)form Point Spread Function (PSF)• Analysis of PSF for higher order Analysis of PSF for higher order
aberrations and other data formatsaberrations and other data formats
Programmable Data Sample PointsProgrammable Data Sample Points
Multiplying the Number of Sites
Higher Local Density of Sites
Overlay of Two Sets of Site Configuration
Refractive Error MeasurementsRefractive Error MeasurementsMyopiaMyopia HyperopiaHyperopia
Retinal Spot Diagram/Point Retinal Spot Diagram/Point Spread FunctionSpread Function
X, µm20100-10-20
Y,
µm
40
30
20
10
0
-10
-20
Refraction MapRefraction MapRetinal Spot DiagramRetinal Spot Diagram
Wavefront MapWavefront MapAblation MapAblation Map
Data DisplaysData Displays
Tracey’s Key Advantage:Tracey’s Key Advantage:
Rapid, point-by-point analysis ofRapid, point-by-point analysis of256 data points avoids data confusion256 data points avoids data confusion
associated with simultaneous data associated with simultaneous data measurements, therefore, all eyesmeasurements, therefore, all eyes
(highly irregular) can be measured. All (highly irregular) can be measured. All points in any pupil size (2-8mm) each points in any pupil size (2-8mm) each
with full dynamic range (+/- 15 D).with full dynamic range (+/- 15 D).
NO COMPROMISES!NO COMPROMISES!
Baylor Clinical Study Baylor Clinical Study (100 eyes)(100 eyes)by Doug Koch, MDby Doug Koch, MD
-13D
+7D
Validation StudiesValidation StudiesThree independent studies of Three independent studies of Tracey vs. Manifest RefractionTracey vs. Manifest Refraction• Koch et al - 100 eyesKoch et al - 100 eyes• Slade et al - 42 eyesSlade et al - 42 eyes• Schalhorn et al - 106 eyesSchalhorn et al - 106 eyes
ResultsResults• Accuracy to manifestAccuracy to manifest <0.12 D<0.12 D• ReproducibilityReproducibility <0.12 D<0.12 D
The The iiTraceTrace
Normal EyeNormal Eye
Irregular EyeIrregular Eye
UCVA vs BCVAUCVA vs BCVA
Post Post LASIKLASIK
Full Corneal TopographyFull Corneal Topography
Full Corneal TopographyFull Corneal Topography
KeratoconuKeratoconuss
NormalNormal
iTrace Measures iTrace Measures Accommodation MechanismAccommodation Mechanism
Very Spherical Very Spherical AccommodationAccommodation
Variations inVariations in
Mapping Mapping
AccommodativeAccommodative
Power in the Power in the
Natural Natural
Crystalline LensCrystalline Lens
asas
Measured byMeasured by
iTraceiTrace
Vertical Cyl
Horizontal Cyl Sphere
Coma
Crystalens Accommodative ArchingCrystalens Accommodative Arching
73 Year Old Male
Overall Refraction change is 0.5D but Central Cylinder 2.5 D adds Depth of
Field to Enhance Accommodative Effect
MultiFocal IOL Analysis withMultiFocal IOL Analysis withii TraceTrace
• PSF AnalysisPSF Analysis• Modulation Transfer Function (MTF)obust Modulation Transfer Function (MTF)obust
AberrometerAberrometer Pupil Dependent AnalysisPupil Dependent Analysis Multi-Zone Refraction AnalysisMulti-Zone Refraction Analysis
• Retinal Spot Diagram Retinal Spot Diagram Conoid of Sturm Dynamic AnalysisConoid of Sturm Dynamic Analysis
• Complete Corneal Topography AnalysisComplete Corneal Topography Analysis
• Separates Corneal from Total Aberrations Resulting Separates Corneal from Total Aberrations Resulting in Lenticular (internal ocular) Aberrationsin Lenticular (internal ocular) Aberrations
• Measures AccommodationMeasures Accommodation
Multifocal Acrylic IOLMultifocal Acrylic IOL
Alcon ReStor LensAlcon ReStor Lens
Monofocal Acrylic IOLMonofocal Acrylic IOL
Alcon SA-60Alcon SA-60
Normal EyeNormal Eye
+0.5 D Hyperope+0.5 D Hyperope
iiTraceTrace SummarySummary• Robust AberrometerRobust Aberrometer
Measures Spatially Resolved Refraction and Measures Spatially Resolved Refraction and Aberrations for ALL eyes – including highly Aberrations for ALL eyes – including highly irregularirregular
Measurement Zone from 2.0 to 8.0 mm (Flexible)Measurement Zone from 2.0 to 8.0 mm (Flexible) Multi-Zone Refraction AnalysisMulti-Zone Refraction Analysis Can do Over-Refraction with Contact Lenses or Can do Over-Refraction with Contact Lenses or
SpectaclesSpectacles Measures Psuedophakic eyesMeasures Psuedophakic eyes
• Complete Corneal Topography AnalysisComplete Corneal Topography Analysis
• Separates Corneal from Total Aberrations Resulting Separates Corneal from Total Aberrations Resulting in Lenticular (internal ocular) Aberrationsin Lenticular (internal ocular) Aberrations
• Measures AccommodationMeasures Accommodation
• Accurate Pupil Size MeasurementAccurate Pupil Size Measurement
Thank youThank youfor your attention.for your attention.
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