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.