PROTEIN SIZE RESOLUTION IN HUMAN EYE LENSES BY DYNAMIC LIGHT-SCATTERING AFTER IN-VIVO MEASUREMENTS

Dynamic light scattering (DLS) measurements were conducted with lowest intensity levels on human eye lenses (3.2 mW/cm(2)) within measuremen t times of 3-5 s, A characterisation of the human eye under in-vivo co nditions along the optical axis is given and a careful interpretation of the data is made, referring not only to in-vitro results of investi gated solutions of lens chemistry and various crystallin fractions but also to measurements performed on intact human lenses under various s cattering angles. The clinical study was expanded to 79 subjects with ages varying from 9 to 85 years with no serious diseases of the ocular lenses, A normalisation of Scheimpflug photography density data to th e data obtained by DLS enables comparison of the two techniques and sh ows good agreement. The bimodal character of the viscoelastic properti es of healthy eye lenses was confirmed; with an assumed viscosity of 2 cP, the mean size parameter of the smaller component is 5.13+/-1.6 nm and of the polymeric fraction 690 nm.