Ocular aberrations with ray tracing and Shack-Hartmann wave-front sensors

Does polarization play a role?

Susana Marcos, Luis Diaz-Santana, Lourdes Llorente, Chris Dainty

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Ocular aberrations were measured in 71 eyes by using two reflectometric aberrometers, employing laser ray tracing (LRT) (60 eyes) and a Shack-Hartmann wave-front sensor (S-H) (11 eyes). In both techniques a point source is imaged on the retina (through different pupil positions in the LRT or a single position in the S-H).The aberrations are estimated by measuring the deviations of the retinal spot from the reference as the pupil is sampled (in LRT) or the deviations of a wave front as it emerges from the eye by means of a lenslet array (in the S-H). In this paper we studied the effect of different polarization configurations in the aberration measurements, including linearly polarized light and circularly polarized light in the illuminating channel and sampling light in the crossed or parallel orientations. In addition, completely depolarized light in the imaging channel was obtained from retinal lipofuscin autofluorescence. The intensity distribution of the retinal spots as a function of entry (for LRT) or exit pupil (for S-H) depends on the polarization configuration. These intensity patterns show bright corners and a dark area at the pupil center for crossed polarization, an approximately Gaussian distribution for parallel polarization and a homogeneous distribution for the autofluorescence case. However, the measured aberrations are independent of the polarization states. These results indicate that the differences in retardation across the pupil imposed by corneal birefringence do not produce significant phase delays compared with those produced by aberrations, at least within the accuracy of these techniques. In addition, differences in the recorded aerial images due to changes in polarization do not affect the aberration measurements in these reflectometric aberrometers.

Original languageEnglish
Pages (from-to)1063-1072
Number of pages10
JournalJournal of the Optical Society of America A: Optics and Image Science, and Vision
Volume19
Issue number6
Publication statusPublished - 2002
Externally publishedYes

Fingerprint

Ray tracing
wave fronts
Aberrations
ray tracing
pupils
aberration
Polarization
sensors
Sensors
polarization
Lasers
Light polarization
polarized light
lasers
deviation
Lipofuscin
retina
Gaussian distribution
configurations
Birefringence

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Computer Vision and Pattern Recognition

Cite this

Ocular aberrations with ray tracing and Shack-Hartmann wave-front sensors : Does polarization play a role? / Marcos, Susana; Diaz-Santana, Luis; Llorente, Lourdes; Dainty, Chris.

In: Journal of the Optical Society of America A: Optics and Image Science, and Vision, Vol. 19, No. 6, 2002, p. 1063-1072.

Research output: Contribution to journalArticle

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