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

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! 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

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

Significant Higher Order Aberrations Trefoil Coma Spherical Aberration

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

Hartmann Shack

Hartmann Shack

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

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

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

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

The iTrace

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

Programmable Data Sample Points

Multiplying the Number of Sites

Higher Local Density of Sites

Overlay of Two Sets of Site Configuration

Refractive Error Measurements Myopia Hyperopia

Retinal Spot Diagram/Point Spread Function

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

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!

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

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

The iTrace

Normal Eye

Irregular Eye

UCVA vs BCVA

Post LASIK

Full Corneal Topography

Full Corneal Topography

Keratoconus

Normal

iTrace Measures Accommodation Mechanism

Very Spherical Accommodation

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

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

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

Multifocal Acrylic IOL Alcon ReStor Lens

Monofocal Acrylic IOL Alcon SA-60

Normal Eye +0.5 D Hyperope

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

Thank you for your attention.