Age-Related Changes In Stiffness Of The Rabbit Lens

Presbyopia is a condition where the eye exhibits a progressively diminished ability to focus on near objects with age. It is a normal physical phenomenon rather than a refractive error, and eventually affects everyone, including myopic or hyperopic one, the only difference is when the presbyopia will occur. Since our country has already entered an aging society, and the number of people with presbyopia has gradually increased, therefore, it is necessary to find available treatments.The crystalline lens is the only refractive media with regulating ability in the ocular refractive system, the change of its biomechanical property has a close relationship to the development of presbyopia. Therefore, the research of lens biomechanical property is helpful for understanding the mechanism of presbyopia and can provide a test method of exploring the physical and chemical treatment of presbyopia.Tension and compression tests were performed on rabbit lenses of different age groups, and the main conclusions were summarized in this paper as following aspects: (1)The weight, thickness, equatorial diameter and maximum load of the rabbit lens increase with aging.(2) In compression tests, the nominal stress, nominal strain and nominal compressive modulus were defined, and calculated nominal compressive modulus value of rabbit lens (3months,6months and9months, respectively) in the elastic range, which were (1.21±0.19) kPa,(2.62±1.13) kPa and (6.46±2.92) kPa, respectively. Nominal compressive modulus value of rabbit lens increases nonlinearly with aging.(3) In tension tests, the change of equatorial diameters of the rabbit lens decreases and the nominal stretching modulus increases with aging.(4) Thus, Stiffness of the rabbit lens increases gradually while its deformation decreases gradually with aging.