title: Changes in monkey crystalline lens spherical aberration during simulated accommodation in a lens stretcher.
abstract: OBJECTIVE
  The purpose of this study was to quantify accommodation-induced changes in the spherical aberration of cynomolgus monkey lenses.
  
  
  METHODS
  Twenty-four lenses from 20 cynomolgus monkeys (Macaca fascicularis; 4.4-16.0 years of age; postmortem time 13.5 ± 13.0 hours) were mounted in a lens stretcher. Lens spherical aberration was measured in the unstretched (accommodated) and stretched (relaxed) states with a laser ray tracing system that delivered 51 equally spaced parallel rays along 1 meridian of the lens over the central 6-mm optical zone. A camera mounted below the lens was used to measure the ray height at multiple positions along the optical axis. For each entrance ray, the change in ray height with axial position was fitted with a third-order polynomial. The effective paraxial focal length and Zernike spherical aberration coefficients corresponding to a 6-mm pupil diameter were extracted from the fitted values.
  
  
  RESULTS
  The unstretched lens power decreased with age from 59.3 ± 4.0 diopters (D) for young lenses to 45.7 ± 3.1 D for older lenses. The unstretched lens shifted toward less negative spherical aberration with age, from -6.3 ± 0.7 μm for young lenses to -5.0 ± 0.5 μm for older lenses. The power and spherical aberration of lenses in the stretched state were independent of age, with values of 33.5 ± 3.4 D and -2.6 ± 0.5 μm, respectively.
  
  
  CONCLUSIONS
  Spherical aberration is negative in cynomolgus monkey lenses and becomes more negative with accommodation. These results are in good agreement with the predicted values using computational ray tracing in a lens model with a reconstructed gradient refractive index. The spherical aberration of the unstretched lens becomes less negative with age.
authors: Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Miami, Florida, United States Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States.
authors: Bianca
authors: B
authors: Maceo Heilman
authors: Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Miami, Florida, United States Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States.
authors: Fabrice
authors: F
authors: Manns
authors: Instituto de Óptica, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors: Alberto
authors: A
authors: de Castro
authors: Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Miami, Florida, United States Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States.
authors: Heather
authors: H
authors: Durkee
authors: Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Miami, Florida, United States.
authors: Esdras
authors: E
authors: Arrieta
authors: Instituto de Óptica, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors: Susana
authors: S
authors: Marcos
authors: Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Miami, Florida, United States Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States Vision Cooperative Research Centre, Brien Holden Vision Institute, University of New South Wales, Sydney, New South Wales, Australia.
authors: Jean-Marie
authors: JM
authors: Parel
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000367:Age Factors; D000818:Animals; D001251:Astigmatism / Q000503:physiopathology; D057108:Corneal Wavefront Aberration / Q000503:physiopathology*; D066298:In Vitro Techniques; D007908:Lens, Crystalline / Q000503:physiopathology*; D008252:Macaca fascicularis; D055620:Optical Phenomena; D012016:Reference Values
keywords: crystalline lens; laser ray tracing; optics; spherical aberration