title: Refractive power and biometric properties of the nonhuman primate isolated crystalline lens.
abstract: Purpose. To characterize the age dependence of shape, refractive power, and refractive index of isolated lenses from nonhuman primates. Methods. Measurements were performed on ex vivo lenses from cynomolgus monkeys (cyno: n = 120; age, 2.7-14.3 years), rhesus monkeys (n = 61; age, 0.7-13.3 years), and hamadryas baboons (baboon: n = 16; age, 1.7-27.3 years). Lens thickness, diameter, and surface curvatures were measured with an optical comparator. Lens refractive power was measured with a custom optical system based on the Scheiner principle. The refractive contributions of the gradient, the surfaces, and the equivalent refractive index were calculated with optical ray-tracing software. The age dependence of the optical and biometric parameters was assessed. Results. Over the measured age range isolated lens thickness decreased (baboon: -0.04, cyno: -0.05, and rhesus: -0.06 mm/y) and equatorial diameter increased (logarithmically for the baboon and rhesus, and linearly for cyno: 0.07 mm/y). The isolated lens surfaces flattened and the corresponding refractive power from the surfaces decreased with age (-0.33, -0.48, and -0.68 D/y). The isolated lens equivalent refractive index decreased (only significant for the baboon, -0.001 D/y), and as a result the total isolated lens refractive power decreased with age (baboon: -1.26, cyno: -0.97, and rhesus: -1.76 D/y). Conclusions. The age-dependent trends in the optical and biometric properties, growth, and aging, of nonhuman primate lenses are similar to those of the pre-presbyopic human lens. As the lens ages, the decrease in refractive contributions from the gradient refractive index causes a rapid age-dependent decrease in maximally accommodated lens refractive power.
authors.affiliation: Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors.forename: David
authors.initials: D
authors.lastname: Borja
authors.forename: Fabrice
authors.initials: F
authors.lastname: Manns
authors.forename: Arthur
authors.initials: A
authors.lastname: Ho
authors.forename: Noel M
authors.initials: NM
authors.lastname: Ziebarth
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Acosta
authors.forename: Esdras
authors.initials: E
authors.lastname: Arrieta-Quintera
authors.forename: Robert C
authors.initials: RC
authors.lastname: Augusteyn
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Parel
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001699:Biometry; D007908:Lens, Crystalline / Q000033:anatomy & histology* / Q000502:physiology*; D008252:Macaca fascicularis; D008253:Macaca mulatta; D048529:Papio hamadryas; D012029:Refraction, Ocular / Q000502:physiology*