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Integration of Aberrometry and Topography with the i Trace System. July 2005 Joe S. Wakil, MD - Tracey Technologies, LLC EyeSys Vision, Inc. Founding Technology Developers:. Vasyl Molebny, DSc Kiev, Ukraine Ioannis Pallikaris, MD Crete, Greece Canadian & Swedish Governments.

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slide1

Integration of Aberrometry and Topography with thei Trace System

July 2005

Joe S. Wakil, MD -

Tracey Technologies, LLC

EyeSys Vision, Inc.

founding technology developers
Founding Technology Developers:

Vasyl Molebny, DSc

Kiev, Ukraine

Ioannis Pallikaris, MD

Crete, Greece

Canadian & Swedish Governments

why aberroscopy
Why Aberroscopy?

Current Laser Technology Permits One to Go Beyond Correction of Sphere and Astigmatism

You Can Now Address Your Patient’s Quality of Vision

High Order Aberrations Define

Quality of Vision

why ray tracing because the eye is not a telescope
Why Ray Tracing?Because… the Eye is NOT a Telescope!

Effects Refraction (ex. Night Myopia)

Refraction is NOT a FIXED Number!

Effects Refraction (Instrument Myopia)

Effects Quality of Vision (Aberrations)

Pupil Size:

Accommodation:

Tear Film:

Where are the Sources of Aberrations?

How do they change with Surgery?

Astigmatism (Irreg.), Sph & other HOA

Astigmatism, Coma & other HOA

Cornea:

Lens:

the eye is not a telescope
EYE

Off-Axis design

No magnification

Variable aperture

Variable detector res.

Accommodation

Changing fixation

Brain image processing

Nature-made

TELESCOPE

On-Axis design

High magnification

Fixed aperture

Constant detector res.

No accommodation

Fixed alignment

Digital image processing

Man-made

The Eye is NOT a Telescope
significant higher order aberrations
Significant Higher Order Aberrations

Trefoil

Coma

Spherical Aberration

aberrometer wavefront technologies
Aberrometer/Wavefront Technologies
  • Hartmann-Shack Lenslet Array
  • Tscherning Aberrometer
  • Differential Skiascopy
  • Ray Tracing

Features:

-Rapid, point by point, IR measurement - no data confusion

-Pupillometry with auto-tracking/capture

-Programmable sampling (256 pts.) in any pupil up to 8mm

-Open Field Fixation – avoid instrument myopia and measure Accommodation

-Corneal Topography integration –

able to measure Lens Aberrations

slide10

Hartmann-ShackWavefront Sensor

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

disadvantages of h s and tscherning
Disadvantages of H-S and Tscherning
  • Measures All Points at Once - Data Confusion, Compromised Resolution
  • Limited Dynamic Range – Cannot Measure Highly Irregular Eyes
  • Highly Sensitive to Noise – Slow, Requires Multiple Scans
  • Expensive Components – High Cost to Purchase and Repair
  • H-S Measures Reverse Aberrations – Not Physiologic with Real Vision especially for High Orders in Accomodation
  • Tscherning Needs 2-D Imaging of Retina - Additional noise and errors
disadvantages of differential skiascopy
Disadvantages of Differential Skiascopy
  • Does NOT Measure Skew Aberrations – Inaccurate WaveFront especially for Trefoil, Quadrafoil, etc.
  • Measures Multiple Points at Once (slit) and only in Perpendicular Direction - Limited WF measurement (axial bias)
  • No Open Field Fixation – Problem of instrument myopia in young patients
measuring corneal aberration without lens or total aberration is of questionable value
*Measuring Corneal Aberrationwithout Lens or Total Aberration is of Questionable Value

Total Ocular Aberrations

Internal Optics Aberrations

Corneal Aberrations

Total Ocular Aberrations

principles of tracey
Principles of Tracey
  • Programmable thin beam ray tracing measuring forward aberrations of the eye
  • Rapid sequential measurement of data points over entire entrance pupil (<50ms)
  • Localization of each reflected retinal spot
  • Integration of individual retinal spots to form Point Spread Function (PSF)
  • Analysis of PSF for higher order aberrations and other data formats
data displays

Retinal Spot Diagram

40

Refraction Map

30

20

Y, µm

10

0

-10

-20

-20

-10

0

10

20

X, µm

Ablation Map

Wavefront Map

Data Displays
slide25

Tracey’s Key Advantage:

Rapid, point-by-point analysis of

256 data points avoids data confusion

associated with simultaneous data measurements, therefore, all eyes

(highly irregular) can be measured. All points in any pupil size (2-8mm) each with full dynamic range (+/- 15 D).

NO COMPROMISES!

validation studies
Validation Studies

Three independent studies of

Tracey vs. Manifest Refraction

  • Koch et al - 100 eyes
  • Slade et al - 42 eyes
  • Schalhorn et al - 106 eyes

Results

  • Accuracy to manifest <0.12 D
  • Reproducibility <0.12 D
variations in mapping accommodative power in the natural crystalline lens as measured by itrace
Variations inMapping AccommodativePower in the Natural Crystalline LensasMeasured byiTrace

Horizontal Cyl

Sphere

Vertical Cyl

Coma

crystalens accommodative arching

73 Year Old Male

Crystalens Accommodative Arching

Overall Refraction change is 0.5D but Central Cylinder 2.5 D adds Depth of Field to Enhance Accommodative Effect

multifocal iol analysis with i trace
MultiFocal IOL Analysis withiTrace
  • PSF Analysis
  • Modulation Transfer Function (MTF)obust Aberrometer
    • Pupil Dependent Analysis
    • Multi-Zone Refraction Analysis
  • Retinal Spot Diagram
    • Conoid of Sturm Dynamic Analysis
  • Complete Corneal Topography Analysis
  • Separates Corneal from Total Aberrations Resulting in Lenticular (internal ocular) Aberrations
  • Measures Accommodation
multifocal acrylic iol
Multifocal Acrylic IOL

Alcon ReStor Lens

normal eye66
Normal Eye

+0.5 D Hyperope

i trace summary
iTraceSummary
  • Robust Aberrometer
    • Measures Spatially Resolved Refraction and Aberrations for ALL eyes – including highly irregular
    • Measurement Zone from 2.0 to 8.0 mm (Flexible)
    • Multi-Zone Refraction Analysis
    • Can do Over-Refraction with Contact Lenses or Spectacles
    • Measures Psuedophakic eyes
  • Complete Corneal Topography Analysis
  • Separates Corneal from Total Aberrations Resulting in Lenticular (internal ocular) Aberrations
  • Measures Accommodation
  • Accurate Pupil Size Measurement
slide79

Thank you

for your attention.