1. Integration of Aberrometry and Topography with the i Trace System
July 2005
Joe S. Wakil, MD -
Tracey Technologies, LLC
EyeSys Vision, Inc.

2. Founding Technology Developers:
Vasyl Molebny, DSc
Kiev, Ukraine
Ioannis Pallikaris, MD
Crete, Greece
Canadian & Swedish Governments

3. 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

4. Why Ray Tracing? Because… the Eye is NOT a Telescope!
Pupil Size:
Accommodation:
Tear Film:
Effects Refraction (ex. Night Myopia)
Refraction is NOT a FIXED Number!
Effects Refraction (Instrument Myopia)
Effects Quality of Vision (Aberrations)
Where are the Sources of Aberrations?
How do they change with Surgery?
Cornea:
Lens:
Astigmatism (Irreg.), Sph & other HOA
Astigmatism, Coma & other HOA

5. The Eye is NOT a Telescope
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

6. Significant Higher Order Aberrations
Trefoil
Coma
Spherical Aberration

7. 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

8. Hartmann Shack

9. Hartmann Shack

10. Hartmann-Shack Wavefront Sensor
H/S Photo of patient with tight eye lid courtesy David Williams

11. Tscherning

12. 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

13. Differential Skiascopy

14. 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

15. Total Ocular Aberrations
Internal Optics Aberrations
Corneal Aberrations
Total Ocular Aberrations
*Measuring Corneal Aberration without Lens or Total Aberration is of Questionable Value

16. The iTrace

17. 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

18. Programmable Data Sample Points

19. Multiplying the Number of Sites

20. Higher Local Density of Sites

21. Overlay of Two Sets of Site Configuration

22. Refractive Error Measurements
Myopia
Hyperopia

23. Retinal Spot Diagram/Point Spread Function

24. Data Displays Retinal Spot Diagram Refraction Map Ablation Map
X, µm 20 10
-10
-20
Y, µm 40 30
Refraction Map
Retinal Spot Diagram
Wavefront Map
Ablation Map

25. Tracey’s Key Advantage: NO COMPROMISES!
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!

26. Baylor Clinical Study (100 eyes) by Doug Koch, MD

27. Validation Studies Three independent studies of
Tracey vs. Manifest Refraction
Koch et al eyes
Slade et al - 42 eyes
Schalhorn et al eyes
Results
Accuracy to manifest <0.12 D
Reproducibility <0.12 D

28. The iTrace

29. Normal Eye

30. Irregular Eye

31. UCVA vs BCVA

32. Post LASIK

33. Full Corneal Topography

34. Full Corneal Topography

35. Keratoconus

36. Normal

37. iTrace Measures Accommodation Mechanism

38. Very Spherical Accommodation

39. Variations in Mapping Accommodative Power in the Natural Crystalline Lens as Measured by iTrace
Horizontal Cyl
Sphere
Vertical Cyl
Coma

40. Crystalens 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

41. MultiFocal IOL Analysis with i Trace
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

42. Multifocal Acrylic IOL
Alcon ReStor Lens

54. Monofocal Acrylic IOL
Alcon SA-60

66. Normal Eye
+0.5 D Hyperope

78. iTrace Summary 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

79. Thank you
for your attention.