title: Tomographic method for measurement of the gradient refractive index of the crystalline lens. I. The spherical fish lens.
abstract: We present an iterative tomographic algorithm to reconstruct refractive-index profiles for meridional planes of the lens of the spherical fish eye from measurements of deflection angles of refracted rays. Numerical simulations show that the algorithm allows accuracy up to the fourth decimal place, provided that the refractive index can be regarded as an analytical function of the radial coordinate and the experimental errors are neglected. An experimental demonstration is given by applying the algorithm to retrieve the refractive-index profile of a spherical fish lens. The method is conceptually simple and does not require matching of the index of the surrounding medium to that of the surface of the lens, and the related iterative algorithm rapidly converges.
authors.affiliation: Area de Optica, Departamento de Fisica Aplicada, Campus Sur, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain. fagoeva@usc.es
authors.forename: Eva
authors.initials: E
authors.lastname: Acosta
authors.forename: Daniel
authors.initials: D
authors.lastname: Vazquez
authors.forename: Leon
authors.initials: L
authors.lastname: Garner
authors.forename: George
authors.initials: G
authors.lastname: Smith
mesh_terms: D000818:Animals; D019781:Corneal Topography / Q000379:methods*; D005399:Fishes; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007908:Lens, Crystalline / Q000033:anatomy & histology / Q000502:physiology*; D012029:Refraction, Ocular / Q000502:physiology*; D012031:Refractometry / Q000379:methods*; D042262:Retinoscopy / Q000379:methods*; D041622:Tomography, Optical / Q000379:methods*