Wavefront Aberration Measurements by the Fourrierdriven WaveScan and the Zernickedriven LADARWave Ha

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Wavefront Aberration Measurements by the
Fourrier-driven WaveScanand the Zernicke-driven
LADARWave Hartmann-Shack Aberrometers
aComparative Study

• Stefanie Knapp, MD
• Shady T. Awwad, MD
• James P. McCulley, MD

The University of Texas Southwestern Medical
Center at Dallas
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Purpose

• To compare the pattern and degree of higher and
  lower orderaberrations measurement by two
  different Hartmann-Shack aberrometers
• Fourrier-driven WaveScan
• Zernicke-driven LADARWave.

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Methods

• 36 eyes of 21 custom LASIK candidates were
  enrolled and had their ocular aberrations
  measured and analyzed by the two aberrometers at
  an equal optical zone of 6.0 mm.
• A tunable light intensity source was used to
  control pupillary size.
• The followings were used to compare individual
  aberrations as measured by the two devices
• Mean absolute differences
• Altman-Bland plots
• Pearson correlation coefficients (PCC)
• Vector analysis for directional components

Pupillary Diameter
Optical Zone
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RESULTS
Lower Order Aberrations
PCC Pearsons Correlation Coefficient
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RESULTS
Total HOAs Spherical Aberrations
Total HOAs Total Higher Order Aberrations
PCC Pearsons Correlation Coefficient
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Altman-Bland Graph for Total HOAs
Mean Algebraic difference
Mean Absolute Difference
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Altman-Bland Graph for Spherical Aberration
Mean Algebraic difference
Mean Absolute Difference
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Vector Analysis
Coma Trefoil
PCC Pearsons Correlation Coefficient
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CONCLUSION

• WaveScan and LADARWave show
• Very similar lower order aberrations measurement
  profiles
• but markedly different higher order aberrations
  measurements