Age-dependent Fourier model of the shape of the isolated ex vivo human crystalline lens

Raksha Urs, Arthur Ho, Fabrice Manns, Jean Marie Parel

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Purpose: To develop an age-dependent mathematical model of the zero-order shape of the isolated ex vivo human crystalline lens, using one mathematical function, that can be subsequently used to facilitate the development of other models for specific purposes such as optical modeling and analytical and numerical modeling of the lens. Methods: Profiles of whole isolated human lenses (n=30) aged 20-69, were measured from shadow-photogrammetric images. The profiles were fit to a 10th-order Fourier series consisting of cosine functions in polar-co-ordinate system that included terms for tilt and decentration. The profiles were corrected using these terms and processed in two ways. In the first, each lens was fit to a 10th-order Fourier series to obtain thickness and diameter, while in the second, all lenses were simultaneously fit to a Fourier series equation that explicitly include linear terms for age to develop an age-dependent mathematical model for the whole lens shape. Results: Thickness and diameter obtained from Fourier series fits exhibited high correlation with manual measurements made from shadow-photogrammetric images. The root-mean-squared-error of the age-dependent fit was 205μm. The age-dependent equations provide a reliable lens model for ages 20-60. years. Conclusion: The contour of the whole human crystalline lens can be modeled with a Fourier series. Shape obtained from the age-dependent model described in this paper can be used to facilitate the development of other models for specific purposes such as optical modeling and analytical and numerical modeling of the lens.

Original languageEnglish (US)
Pages (from-to)1041-1047
Number of pages7
JournalVision Research
Volume50
Issue number11
DOIs
StatePublished - Jun 2010

Keywords

  • Accommodation
  • Human crystalline lens shape
  • Mechanical model
  • Optical model
  • Presbyopia

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems

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