Numerical study of the influence of the shell structure of the crystalline lens on the refractive properties of the human eye

In this paper, the numerical model of the refractive properties of the human eye is given. A special account is given of the laminated structure of the crystalline lens. The crystalline lens is presented in the form of hundreds of shells with rotational symmetry, and with the refractive index constant within each shell. The shells have the form of two semi‐ellipsoids joined along the equator. The refractive index increases from the cortical shell to the inner one, according to the exponential dependency. The cornea, approximated by two ellipsoidal surfaces, is added in front of the crystalline lens. A ray‐tracing procedure is applied to study the refractive properties of such a system: refractive power, spherical aberration and energy distribution. The optical properties of the given model are analysed by changing some parameters such as refractive index profile and number of shells. Calculations show that the gradient of the refractive index inside the crystalline lens results in the generation of many focal planes in such an optical system.

[1]  Melanie C. W. Campbell,et al.  Measurement of refractive index in an intact crystalline lens , 1984, Vision Research.

[2]  J. W. Warnicki,et al.  Corneal topography , 1992, 1992 14th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[3]  G Smith,et al.  Nondestructive Method of Constructing Three‐Dimensional Gradient Index Models for Crystalline Lenses: I. Theory and Experiment , 1988, American journal of optometry and physiological optics.

[4]  C. Edmund.  Determination of the corneal thickness profile by optical pachometry , 1987, Acta ophthalmologica.

[5]  I H Al-Ahdali,et al.  Examination of the effect of the fibrous structure of a lens on the optical characteristics of the human eye: a computer-simulated model. , 1995, Applied optics.

[6]  B. Pierscionek.  Presbyopia and the effect of refractive index. , 1990 .

[7]  L. Garner,et al.  Change with age of the refractive index gradient of the human ocular lens. , 1994, Investigative ophthalmology & visual science.

[8]  Michel Millodot,et al.  Contribution of the cornea and lens to the spherical aberration of the eye , 1979, Vision Research.

[9]  J. W. Warnicki,et al.  Corneal Topography , 1992, Springer New York.

[10]  W. S. Jagger.  The refractive structure and optical properties of the isolated crystalline lens of the cat , 1990, Vision Research.

[11]  S. Trokel.  The physical basis for transparency of the crystalline lens. , 1962, Investigative ophthalmology.

[12]  Jane F. Koretz,et al.  Analysis of human crystalline lens curvature as a function of accommodative state and age , 1984, Vision Research.

[13]  K. Iwata,et al.  Model of refractive-index distribution in the rabbit crystalline lens. , 1968, Journal of the Optical Society of America.

[14]  G Smith,et al.  Determination and modeling of the 3-D gradient refractive indices in crystalline lenses. , 1988, Applied optics.

[15]  P. K. Jensen,et al.  In vitro measurement of corneal strain, thickness, and curvature using digital image processing. , 2009, Acta ophthalmologica Scandinavica.

[16]  Hermann von Helmholtz,et al.  Treatise on Physiological Optics , 1962 .

[17]  J. Rowsey,et al.  Corneal Topography: Corneascope , 1981 .

[18]  G J Wang,et al.  Wide‐Angle Optical Model of the Eye , 1972, American journal of optometry and physiological optics.

[19]  D A Atchison,et al.  The optical modelling of the human lens , 1991, Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians.

[20]  F. Berny,et al.  Contribution of the crystalline lens to the spherical aberration of the eye. , 1973, Journal of the Optical Society of America.

[21]  R. Lowe,et al.  Anterior lens curvature. Comparisons between normal eyes and those with primary angle-closure glaucoma. , 1972, The British journal of ophthalmology.

[22]  W. Lotmar.  Theoretical Eye Model with Aspherics , 1971 .

[23]  J. Sivak,et al.  Spherical aberration of the crystalline lens , 1983, Vision Research.

[24]  B. Clark,et al.  Radius of curvature of the anterior lens surface. Correlations in normal eyes and in eyes involved with primary angle-closure glaucoma. , 1973, The British journal of ophthalmology.

[25]  P. Kiely,et al.  The Mean Shape of the Human Cornea , 1982 .

[26]  B. Philipson,et al.  Normal human lens - the distribution of protein. , 1981, Experimental eye research.

[27]  Henryk T. Kasprzak,et al.  A new analytical approximation of corneal topography , 1996 .