Dynamic visco-elastic properties of rabbit and human crystalline lens have been investigated in vitro with dynamic rheometer.
The frequency of oscillation employed was 0.01 to 25c/sec. Elastic modulus and loss tangent of the lens showed dependency to temperature and frequency of oscillation. When the amplitude of oscillation was higher than 0.03mm the lens showed non-linear visco-elasticity.
Deformation process of human crystalline lens in vivo was followed by the ultra-sound echogram.
The deformation of the lens was the function of the time and stress, and time relationship of the lens was the same as those of visco-elastic materials. This stress and time relationship of the lens during accomodation was confirmed by the data obtained by photo-phacometry.