Effect of sampling on real ocular aberration measurements.

The minimum number of samples necessary to fully characterize the aberration pattern of the eye is a question under debate in the clinical as well as the scientific community. We performed repeated measurements of ocular aberrations in 12 healthy nonsurgical human eyes and in 3 artificial eyes, using different sampling patterns (hexagonal, circular, and rectangular with 19 to 177 samples, and 3 radial patterns with 49 sample coordinates corresponding to zeros of the Albrecht, Jacobi, and Legendre functions). For each measurement set we computed two different metrics based on the root-mean-square (RMS) of difference maps (RMS_Diff) and the proportional change in the wavefront (W%). These metrics are used to compare wavefront estimates as well as to summarize results across eyes. We used computer simulations to extend our results to "abnormal eyes" (keratoconic, post-LASIK, and post-radial keratotomy eyes). We found that the spatial distribution of the samples can be more important than the number of samples for both our measured as well as our simulated "abnormal" eyes. Experimentally, we did not find large differences across patterns except, as expected, for undersampled patterns.

[1]  Edwin J Sarver,et al.  Are all aberrations equal? , 2002, Journal of refractive surgery.

[2]  S. Barbero,et al.  On-Eye Measurement of Optical Performance of Rigid Gas Permeable Contact Lenses Based on Ocular and Corneal Aberrometry , 2003, Optometry and vision science : official publication of the American Academy of Optometry.

[3]  David A. Atchison,et al.  Measurement of monochromatic ocular aberrations of human eyes as a function of accommodation by the howland aberroscope technique , 1995, Vision Research.

[4]  S A Burns,et al.  Measurement of the wave-front aberration of the eye by a fast psychophysical procedure. , 1998, Journal of the Optical Society of America. A, Optics, image science, and vision.

[5]  T. Hebert,et al.  Adaptive optics scanning laser ophthalmoscopy. , 2002, Optics express.

[6]  M. Losada,et al.  Aberrations and Relative Efficiency of Light Pencils in the Living Human Eye , 1997, Optometry and vision science : official publication of the American Academy of Optometry.

[7]  Susana Marcos,et al.  Ocular aberrations with ray tracing and Shack-Hartmann wave-front sensors: does polarization play a role? , 2002, Journal of the Optical Society of America. A, Optics, image science, and vision.

[8]  Sergio Barbero,et al.  Optical aberrations of intraocular lenses measured in vivo and in vitro. , 2003, Journal of the Optical Society of America. A, Optics, image science, and vision.

[9]  Sergio Barbero,et al.  Myopic versus hyperopic eyes: axial length, corneal shape and optical aberrations. , 2004, Journal of vision.

[10]  Nikole L. Himebaugh,et al.  On-Eye Evaluation of Optical Performance of Rigid and Soft Contact Lenses , 2001, Optometry and vision science : official publication of the American Academy of Optometry.

[11]  Austin Roorda,et al.  Predicting and Assessing Visual Performance with Multizone Bifocal Contact Lenses , 2003, Optometry and vision science : official publication of the American Academy of Optometry.

[12]  R Navarro,et al.  Ocular aberrations before and after myopic corneal refractive surgery: LASIK-induced changes measured with laser ray tracing. , 2001, Investigative ophthalmology & visual science.

[13]  R. Nuijts,et al.  Wavefront‐guided versus standard laser in situ keratomileusis to correct low to moderate myopia , 2002, Journal of cataract and refractive surgery.

[14]  R. Dhillon,et al.  For the safe use of lasers , 1989 .

[15]  Salvador Bará,et al.  Sampling geometries for ocular aberrometry: A model for evaluation of performance. , 2005, Optics express.

[16]  M J Cox,et al.  Effect of aging on the monochromatic aberrations of the human eye. , 1999, Journal of the Optical Society of America. A, Optics, image science, and vision.

[17]  Ronald Cubalchini,et al.  Modal wave-front estimation from phase derivative measurements , 1979 .

[18]  Sergio Barbero,et al.  Validation of the estimation of corneal aberrations from videokeratography in keratoconus. , 2002, Journal of refractive surgery.

[19]  R A Applegate,et al.  Changes in corneal wavefront aberrations with aging. , 1999, Investigative ophthalmology & visual science.

[20]  Gleb Vdovin,et al.  Hartmann-Shack test with random masks for modal wavefront reconstruction. , 2005, Optics express.

[21]  Charles E Campbell.  A test eye for wavefront eye refractors. , 2005, Journal of refractive surgery.

[22]  Salvador Bará,et al.  Hartmann sensing with Albrecht grids , 1997 .

[23]  L. Thibos,et al.  Standards for reporting the optical aberrations of eyes. , 2002, Journal of refractive surgery.

[24]  P. M. Prieto,et al.  Effects of interactions among wave aberrations on optical image quality , 2006, Vision Research.

[25]  Pablo Artal,et al.  Corneal optical aberrations and retinal image quality in patients in whom monofocal intraocular lenses were implanted. , 2002, Archives of ophthalmology.

[26]  T. Seiler,et al.  Ocular optical aberrations after photorefractive keratectomy for myopia and myopic astigmatism. , 2000, Archives of ophthalmology.

[27]  Theo Seiler,et al.  Clinical results of wavefront‐guided laser in situ keratomileusis 3 months after surgery , 2001, Journal of cataract and refractive surgery.

[28]  K. Pesudovs,et al.  Impact of Zernike-fit error on simulated high- and low-contrast acuity in keratoconus: implications for using Zernike-based corrections. , 2006, Journal of The Optical Society of America A-optics Image Science and Vision.

[29]  Junzhong Liang,et al.  Objective measurement of wave aberrations of the human eye with the use of a Hartmann-Shack wave-front sensor. , 1994, Journal of the Optical Society of America. A, Optics, image science, and vision.

[30]  W N Charman,et al.  Aberrations and myopia , 2005, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[31]  E. Acosta,et al.  Integral evaluation of the modal phase coefficients in curvature sensing: Albrecht’s cubatures , 1996 .

[32]  S. Klyce,et al.  Zernike polynomial fitting fails to represent all visually significant corneal aberrations. , 2003, Investigative ophthalmology & visual science.

[33]  W. Southwell.  Wave-front estimation from wave-front slope measurements , 1980 .

[34]  N. Davies,et al.  Repeatability of Ocular Wavefront Measurement , 2003, Optometry and vision science : official publication of the American Academy of Optometry.

[35]  D R Williams,et al.  Supernormal vision and high-resolution retinal imaging through adaptive optics. , 1997, Journal of the Optical Society of America. A, Optics, image science, and vision.