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A Method for Estimating the Wavefront Aberrations with Missing Spot Data in a Hartmann-Shack Aberrometer

  • R. Burman
  • A. Ommani
  • D. Thapa
  • K. Raahemifar
  • N. Hutchings
  • V. Lakshminarayanan
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 166)

Abstract

This paper reports a method of wavefront sensing based on Hartmann-Shack (HS) centroid displacements and predicts the number of HS spots that can be successfully deleted without hampering the prediction of the defocus of the computed wavefront, described via Zernike polynomials. The deletion of the HS spots was randomized. The experiment was performed on real data acquired through a custom made aberrometer tested on a model eye with various axial lengths to simulate refractive errors (defocus) between ~±1.50D. Estimates of defocus were made from each of 1000 runs at each axial length. The paper presents the standard deviation of error and mean error for 1000 trials. The results indicate that as high as 50 % of the HS spots can be deleted without affecting the estimation of spherical defocus, within typical clinically acceptable limits of \(\pm 0.25{\text{D}}\).

Keywords

Axial Length Refractive Error Bright Pixel Wavefront Aberration Subject Image 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. 1.
    Thapa D, Fleck A, Lakshminarayanan V, Bobier WR (2011) Ocular wavefront aberration and refractive error in pre-school children. J Mod Opt 58:1681–1689CrossRefADSGoogle Scholar
  2. 2.
    Liang J, Grimm B, Goelz S, Bille JF (1994) Objective measurement of wave aberrations of the human eye with the use of a Hartmann-Shack wave-front sensor. J Opt Soc Am A 11:1949–1957CrossRefADSGoogle Scholar
  3. 3.
    Lakshminarayanan V, Felck A (2011) Zernike Polynomials: a guide. J Mod Opt 58:545–561CrossRefADSGoogle Scholar
  4. 4.
    Neal DR, Topa DM, Copland J (2001) Effect of lenslet resolution on the accuracy of ocular wavefront measurements. In: BIOS, the international symposium on biomedical optics. International Society for Optics and Photonics, Bellingham, pp 78–91Google Scholar
  5. 5.
    Thibos LN, Hong X (1999) Clinical applications of the Shack-Hartmann aberrometer. Optom Vis Sci 76:817–825CrossRefGoogle Scholar
  6. 6.
    Diaz-Santana L, Guériaux V, Arden G, Gruppetta S (2007) New methodology to measure the dynamics of ocular wave front aberrations during small amplitude changes of accommodation. Opt Express 15(9):5649–5663CrossRefADSGoogle Scholar

Copyright information

© Springer India 2015

Authors and Affiliations

  • R. Burman
    • 1
  • A. Ommani
    • 2
  • D. Thapa
    • 2
  • K. Raahemifar
    • 3
  • N. Hutchings
    • 2
  • V. Lakshminarayanan
    • 2
    • 4
  1. 1.Department of Electronics and Telecommunication EngineeringJadavpur UniversityKolkataIndia
  2. 2.School of Optometry and Vision ScienceUniversity of WaterlooWaterlooCanada
  3. 3.Department of Electrical and Computer EngineeringRyerson UniversityTorontoCanada
  4. 4.Department of PhysicsUniversity of WaterlooWaterlooCanada

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