1. Wavefront by Method of Ray Tracing: Because the Eye is Not a Telescope
Joe S. Wakil, M.D.
Chairman, Tracey Technologies, LLC
and EyeSys Vision, Inc.
Speaker has a Financial Interest

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

3. Why Dynamic 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

4. 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

5. 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
-VISX license for Custom LASIK

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

7. 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

8. Data Sample Points
Data Sample Points

9. Multiplying the Number of Sites

10. Higher Local Density of Sites

11. Overlay of Two Sets of Site Configuration

12. Ray Tracing Objective lens Input Beam Retina Eye optics Position
sensitive
detector

13. Ray Tracing Objective lens Retina Eye optics Position sensitive
detector

14. Ray Tracing Objective lens Retina Eye optics Position sensitive
detector

15. Ray Tracing Objective lens Retina Eye optics Position sensitive
detector

16. Ray Tracing Objective lens Retina Eye optics Position sensitive
detector

17. Ray Tracing Objective lens Retina Eye optics Position sensitive
detector

38. Refractive Error Measurements
Myopia
Hyperopia

39. Retinal Spot Diagram/Point Spread Function

40. 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

41. Tracey Analysis Conoid of Sturm Evaluation Contrast Sensitivity Data
Depth of Field Analysis
Individual Data Point PSF’s
Zernike Calculations

62. Diagnostic Capabilities
Determine Higher Order Aberrations
True Point Spread Function Presentation
Optical Media Opacity Mapping
Integrated Corneal Topography

63. Validation Studies Three independent studies of
Tracey vs. Manifest Refraction
Koch et al - 58 eyes
Slade et al - 42 eyes
Schalhorn et al eyes
Results
Accuracy to manifest <0.12 D
Reproducibility <0.12 D

67. Post LASIK

68. Post LASIK

69. Post LASIK

70. Keratoconus

71. Normal

72. Normal

73. Accommodating IOL Change due to Accommodation Near Fixation
Far Fixation

74. Advantages of Ray Tracing Aberrometry Combined with Corneal Topography - iTrace
Robust dynamic range to measure highly irregular eyes including immediately post-op
Multi-Zone Refraction in seconds to measure variations in refraction from normal night myopes to post-op results saving chair time
Able to separate Corneal from Lenticular (internal ocular) sources of aberrations with EyeSys Corneal Topography
Improved Diagnostic Wavefront to help in patient selection including Custom LASIK and IOL procedures

75. Conclusion
The Tracey iTrace brings a new standard of care in completely assessing vision in terms of quality of vision (aberrometry) and corneal topography to progress visual correction diagnosis and treatments to its ultimate goals.