[The tension of zonule and aging changes of ciliary bodies]

The zonular tension was studied in thirty fixed autopsy eyes (7 eyes under 30 years old, 15 eyes seventh decade and 8 eyes over 85 years old) by pulling the lens backward, and the surface structure of the ciliary body was studied histopathologically following the removal of zonular fibers. The tension for breaking zonules was 49.1 +/- 8.0 gm in younger age group, and 35.3 +/- 8.2 gm in older age group. The zonules in the younger age group was statistically stronger than those in the older age group (p less than 0.01). This breaking occurred at the region adjacent to the ciliary body in the younger age group, but at the region adjacent to the lens in the older age group. The internal surface of the pars plicata and the anterior pars plana was characterized by regular meridional ridges and grooves in the younger age group but was irregular in older age group. In the older age group, grooves among the ridges were wide. In the posterior pars plana, spine-like structure was observed learning parallel toward the lens along the course of zonular fibers. These ageing changes of zonules and ciliary body may depend on the load for the accommodation.