Influence of shape and gradient refractive index in the accommodative changes of spherical aberration in nonhuman primate crystalline lenses

Alberto de Castro, Judith Birkenfeld, Bianca Maceo, Fabrice Manns, Esdras Arrieta, Jean Marie Parel, Susana Marcos

Research output: Contribution to journalArticle

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Abstract

Purpose. To estimate changes in surface shape and gradient refractive index (GRIN) profile in primate lenses as a function of accommodation. To quantify the contribution of surface shape and GRIN to spherical aberration changes with accommodation. Methods. Crystalline lenses from 15 cynomolgus monkeys were studied in vitro under different levels of accommodation produced by a stretching system. Lens shape was obtained from optical coherence tomography (OCT) cross-sectional images. The GRIN was reconstructed with a search algorithm using the optical path measured from OCT images and the measured back focal length. The spherical aberration of the lens was estimated as a function of accommodation using the reconstructed GRIN and a homogeneous refractive index. Results. The lens anterior and posterior radii of curvature decreased with increasing lens power. Both surfaces exhibited negative asphericities in the unaccommodated state. The anterior surface conic constant shifted toward less negative values with accommodation, while the value of the posterior remained constant. GRIN parameters remained constant with accommodation. The lens spherical aberration with GRIN distribution was negative and higher in magnitude than that with a homogeneous equivalent refractive index (by 29% and 53% in the unaccommodated and fully accommodated states, respectively). Spherical aberration with the equivalent refractive index shifted with accommodation toward negative values (-0.070 lm/diopter [D]), but the reconstructed GRIN shifted it farther (-0.124 lm/ D). Conclusions. When compared with the lens with the homogeneous equivalent refractive index, the reconstructed GRIN lens has more negative spherical aberration and a larger shift toward more negative values with accommodation.

Original languageEnglish (US)
Pages (from-to)6197-6207
Number of pages11
JournalInvestigative Ophthalmology and Visual Science
Volume54
Issue number9
DOIs
StatePublished - Sep 18 2013

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Keywords

  • Accommodation
  • Crystalline lens
  • Gradient refractive index
  • GRIN
  • Spherical aberration

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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