水晶体の粘弾性 : 生物のレオロジー
スポンサーリンク
概要
- 論文の詳細を見る
The crystalline lens of human eyes plays a major role in their accommodation. It has long been believed that the lens is of an elastic material. This elasticity has been one of the bases of the accommodation theory. According to Kikkawa and Sato (1963) and Fukuda (1963), the lens is of a viscoelastic material. This conception of the properties of the lens is, however, does not hold with the capacity of human eyes for first accommodation that is ca. one second. Their observation is quasi-static, their time scale of observation being minutes and hours. So it is more adequate to investigate viscoelastic property on shorter time scale, that is dynamic property, to know the deformation characteristics of the lens. The viscoelastic property of the crystalline lens has been investigated with a dynamic rheometer (Fukuda and Data 1962, manufactured by the Rion Co. Ltd). The elastic modulus and loss tangent of crystalline lens are dependent on the frequency of oscillation and the temperature. There is no large difference between the dynamic property of 0.01cps and 1cps, indicating that the dynamic property of lens cannot explain human crystalline lens in vivo during the accommodation has been traced with ultrasound echogram and phacometry. the lens showed viscoelastic characteristics, its stress time curve have shown creep and elastic after-effect. The retardation time was very short as compared with that of lens in vitro,. Mizukawa et al. (1960) investigated the accommodation process precisely with their Accommodometer, and found that the refracting power (diopter) of the crystalline lens was a function of time. The dipter-time curve of the lens closely resembled the stress-time curve of any viscoelastic materials, with apparent creep and elastic after-effect (Nakabayashi et al., 1963). Their results are in good accordance with our results obtained from the ultrasound echogram and phacometry. The source of the difference of rheological property of the lens between in vitro and in vivo is not.
- 社団法人日本材料学会の論文
- 1964-05-15