Wavefront by Method of Ray Wavefront by Method of Ray Tracing: Because the Eye is Tracing: Because the Eye is

Not a TelescopeNot a Telescope

Joe S. Wakil, M.D.Joe S. Wakil, M.D.Chairman, Tracey Technologies, LLCChairman, Tracey Technologies, LLC

and EyeSys Vision, Inc.and EyeSys Vision, Inc.

Speaker has a Financial InterestSpeaker has a Financial Interest

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 Dynamic Ray Tracing?Why Dynamic 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:

AccommodatioAccommodation:n:

Tear Film:Tear Film:

Astigmatism (Irreg.), Sph & other Astigmatism (Irreg.), Sph & other HOAHOA

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

Aberrometer/Wavefront Aberrometer/Wavefront TechnologiesTechnologies

• Hartmann-Shack Lenslet ArrayHartmann-Shack Lenslet Array• Tscherning AberrometerTscherning Aberrometer• Differential SkiascopyDifferential Skiascopy• Ray TracingRay Tracing

Features:Features:-Rapid, point by point, IR measurement - -Rapid, point by point, IR measurement -

no data confusion no data confusion-Pupillometry with auto-tracking/capture -Pupillometry with auto-tracking/capture -Programmable sampling (256 pts.) in -Programmable sampling (256 pts.) in

any pupil up to 8mmany pupil 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-VISX license for Custom LASIK-VISX license for Custom LASIK

H/S Photo of patient with tight eye lid courtesy David WilliamsH/S Photo of patient with tight eye lid courtesy David Williams

Hartmann-Shack Hartmann-Shack Wavefront SensorWavefront Sensor

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

Data Sample Points

Data Sample PointsData Sample Points

Multiplying the Number of Sites

Higher Local Density of Sites

Overlay of Two Sets of Site Configuration

Position sensitive detector

Objective lens

Eye optics

Retina

Ray TracingRay Tracing

Input BeamInput Beam

Position sensitive detector

Objective lens

Retina

Ray TracingRay Tracing

Eye optics

Position sensitive detector

Objective lens

Eye optics

Retina

Ray TracingRay Tracing

Position sensitive detector

Objective lens

Eye optics

Retina

Ray TracingRay Tracing

Position sensitive detector

Objective lens

Eye optics

Retina

Ray TracingRay Tracing

Position sensitive detector

Objective lens

Eye optics

Retina

Ray TracingRay Tracing

Refractive Error MeasurementsRefractive Error Measurements

MyopiaMyopia 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 AnalysisTracey Analysis

• Conoid of Sturm EvaluationConoid of Sturm Evaluation• Contrast Sensitivity DataContrast Sensitivity Data• Depth of Field AnalysisDepth of Field Analysis• Individual Data Point PSF’sIndividual Data Point PSF’s• Zernike CalculationsZernike Calculations

Diagnostic CapabilitiesDiagnostic Capabilities

• Determine Higher Order AberrationsDetermine Higher Order Aberrations• True Point Spread Function True Point Spread Function

PresentationPresentation• Optical Media Opacity MappingOptical Media Opacity Mapping• Integrated Corneal TopographyIntegrated Corneal Topography

Validation StudiesValidation Studies

Three independent studies of Three independent studies of Tracey vs. Manifest RefractionTracey vs. Manifest Refraction• Koch et al - 58 eyesKoch et al - 58 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

Post Post LASIKLASIK

Post Post LASIKLASIK

Post LASIKPost LASIK

KeratoconuKeratoconuss

NormalNormal

NormalNormal

Accommodating IOL

Change due to Accommodation

Far Fixation

Near Fixation

Advantages of Ray Tracing Advantages of Ray Tracing Aberrometry Combined with Corneal Aberrometry Combined with Corneal

Topography - iTraceTopography - iTrace• Robust dynamic range to measure highly Robust dynamic range to measure highly

irregular eyes including immediately post-opirregular eyes including immediately post-op• Multi-Zone Refraction in seconds to Multi-Zone Refraction in seconds to

measure variations in refraction from normal measure variations in refraction from normal night myopes to post-op results saving chair night myopes to post-op results saving chair timetime

• Able to separate Corneal from Lenticular Able to separate Corneal from Lenticular (internal ocular) sources of aberrations with (internal ocular) sources of aberrations with EyeSys Corneal TopographyEyeSys Corneal Topography

• Improved Diagnostic Wavefront to help in Improved Diagnostic Wavefront to help in patient selection including Custom LASIK patient selection including Custom LASIK and IOL proceduresand IOL procedures

ConclusionConclusion

The Tracey iTrace brings a new The Tracey iTrace brings a new standard of care in completely standard of care in completely

assessing vision in terms of quality assessing vision in terms of quality of vision (aberrometry) and corneal of vision (aberrometry) and corneal

topography to progress visual topography to progress visual correction diagnosis and treatments correction diagnosis and treatments

to its ultimate goals.to its ultimate goals.