The relationship between accommodative amplitude and the ratio of central lens thickness to its equatorial diameter in vertebrate eyes

Ronald A. Schachar, Barbara K. Pierscionek, Ali Abolmaali, Tri Le

    Research output: Contribution to journalArticle

    8 Citations (Scopus)

    Abstract

    Aim: To determine the relationship between accommodative amplitude and central lens thickness/equatorial lens diameter (CLT/ELD) ratio in vertebrates. Methods: Midsagittal sections of lenses from fixed, post mortem eyes from 125 different vertebrate species were photographed. Their CLT/ELD ratios were correlated with independently published measurements of their accommodative amplitudes. Using the non-linear finite element method (FEM), the efficiency of zonular traction (the absolute change in central radius of curvature per unit force [vertical bar Delta CR vertical bar/F]) for model lenses with CLT/ELD ratios from 0.45 to 0.9 was determined. Results: Vertebrates with CLT/ELD ratios <= 0.6 have high accommodative amplitudes. Zonular traction was found to be most efficient for those model lenses having CLT/ELD ratios <= 0.6. Conclusions: Vertebrates with lenses that have CLT/ELD ratios <= 0.6 - i.e. ``long oval'' shapes - have the greatest accommodative amplitudes; e. g. primates, diving birds and diurnal birds of prey. Vertebrates that have oval or spherical shaped lenses, like owls and most mammals, have low accommodative amplitudes. Zonular traction was found to be most efficient when applied to model lenses with CLT/ELD ratios <= 0.6. The implications of these findings on the mechanism of accommodation are discussed.
    LanguageEnglish
    Pages812-817
    JournalBRITISH JOURNAL OF OPHTHALMOLOGY
    Volume91
    Issue number6
    DOIs
    Publication statusPublished - Jun 2007

    Fingerprint

    vertebrate
    diving
    primate
    finite element method
    curvature
    mammal
    bird

    Cite this

    Schachar, Ronald A. ; Pierscionek, Barbara K. ; Abolmaali, Ali ; Le, Tri. / The relationship between accommodative amplitude and the ratio of central lens thickness to its equatorial diameter in vertebrate eyes. In: BRITISH JOURNAL OF OPHTHALMOLOGY. 2007 ; Vol. 91, No. 6. pp. 812-817.
    @article{426cd9a7c44d42f591d3b1bdf21ffbb3,
    title = "The relationship between accommodative amplitude and the ratio of central lens thickness to its equatorial diameter in vertebrate eyes",
    abstract = "Aim: To determine the relationship between accommodative amplitude and central lens thickness/equatorial lens diameter (CLT/ELD) ratio in vertebrates. Methods: Midsagittal sections of lenses from fixed, post mortem eyes from 125 different vertebrate species were photographed. Their CLT/ELD ratios were correlated with independently published measurements of their accommodative amplitudes. Using the non-linear finite element method (FEM), the efficiency of zonular traction (the absolute change in central radius of curvature per unit force [vertical bar Delta CR vertical bar/F]) for model lenses with CLT/ELD ratios from 0.45 to 0.9 was determined. Results: Vertebrates with CLT/ELD ratios <= 0.6 have high accommodative amplitudes. Zonular traction was found to be most efficient for those model lenses having CLT/ELD ratios <= 0.6. Conclusions: Vertebrates with lenses that have CLT/ELD ratios <= 0.6 - i.e. ``long oval'' shapes - have the greatest accommodative amplitudes; e. g. primates, diving birds and diurnal birds of prey. Vertebrates that have oval or spherical shaped lenses, like owls and most mammals, have low accommodative amplitudes. Zonular traction was found to be most efficient when applied to model lenses with CLT/ELD ratios <= 0.6. The implications of these findings on the mechanism of accommodation are discussed.",
    author = "Schachar, {Ronald A.} and Pierscionek, {Barbara K.} and Ali Abolmaali and Tri Le",
    year = "2007",
    month = "6",
    doi = "10.1136/bjo.2006.107524",
    language = "English",
    volume = "91",
    pages = "812--817",
    journal = "British Journal of Ophthalmology",
    issn = "0007-1161",
    number = "6",

    }

    The relationship between accommodative amplitude and the ratio of central lens thickness to its equatorial diameter in vertebrate eyes. / Schachar, Ronald A.; Pierscionek, Barbara K.; Abolmaali, Ali; Le, Tri.

    In: BRITISH JOURNAL OF OPHTHALMOLOGY, Vol. 91, No. 6, 06.2007, p. 812-817.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - The relationship between accommodative amplitude and the ratio of central lens thickness to its equatorial diameter in vertebrate eyes

    AU - Schachar, Ronald A.

    AU - Pierscionek, Barbara K.

    AU - Abolmaali, Ali

    AU - Le, Tri

    PY - 2007/6

    Y1 - 2007/6

    N2 - Aim: To determine the relationship between accommodative amplitude and central lens thickness/equatorial lens diameter (CLT/ELD) ratio in vertebrates. Methods: Midsagittal sections of lenses from fixed, post mortem eyes from 125 different vertebrate species were photographed. Their CLT/ELD ratios were correlated with independently published measurements of their accommodative amplitudes. Using the non-linear finite element method (FEM), the efficiency of zonular traction (the absolute change in central radius of curvature per unit force [vertical bar Delta CR vertical bar/F]) for model lenses with CLT/ELD ratios from 0.45 to 0.9 was determined. Results: Vertebrates with CLT/ELD ratios <= 0.6 have high accommodative amplitudes. Zonular traction was found to be most efficient for those model lenses having CLT/ELD ratios <= 0.6. Conclusions: Vertebrates with lenses that have CLT/ELD ratios <= 0.6 - i.e. ``long oval'' shapes - have the greatest accommodative amplitudes; e. g. primates, diving birds and diurnal birds of prey. Vertebrates that have oval or spherical shaped lenses, like owls and most mammals, have low accommodative amplitudes. Zonular traction was found to be most efficient when applied to model lenses with CLT/ELD ratios <= 0.6. The implications of these findings on the mechanism of accommodation are discussed.

    AB - Aim: To determine the relationship between accommodative amplitude and central lens thickness/equatorial lens diameter (CLT/ELD) ratio in vertebrates. Methods: Midsagittal sections of lenses from fixed, post mortem eyes from 125 different vertebrate species were photographed. Their CLT/ELD ratios were correlated with independently published measurements of their accommodative amplitudes. Using the non-linear finite element method (FEM), the efficiency of zonular traction (the absolute change in central radius of curvature per unit force [vertical bar Delta CR vertical bar/F]) for model lenses with CLT/ELD ratios from 0.45 to 0.9 was determined. Results: Vertebrates with CLT/ELD ratios <= 0.6 have high accommodative amplitudes. Zonular traction was found to be most efficient for those model lenses having CLT/ELD ratios <= 0.6. Conclusions: Vertebrates with lenses that have CLT/ELD ratios <= 0.6 - i.e. ``long oval'' shapes - have the greatest accommodative amplitudes; e. g. primates, diving birds and diurnal birds of prey. Vertebrates that have oval or spherical shaped lenses, like owls and most mammals, have low accommodative amplitudes. Zonular traction was found to be most efficient when applied to model lenses with CLT/ELD ratios <= 0.6. The implications of these findings on the mechanism of accommodation are discussed.

    U2 - 10.1136/bjo.2006.107524

    DO - 10.1136/bjo.2006.107524

    M3 - Article

    VL - 91

    SP - 812

    EP - 817

    JO - British Journal of Ophthalmology

    T2 - British Journal of Ophthalmology

    JF - British Journal of Ophthalmology

    SN - 0007-1161

    IS - 6

    ER -