Accommodative Changes Observing In Human Ciliary Musle And Lens Using Ultrasound Biomicroscopy

PurposeTo study the changes of the configuration and position of ciliary body and lens response of normal human eyes with advancing age under different accommodative conditions.MethodsThe configuration and position in ciliary body and lens of 70 normal hum- an eyes under different ages groups were observed real-timely and measured by ul- trasound biomicroscopy (UBM), when these eyes focused on given far and near opto- types respectively. All of these parameters between far and near accommodations were compared by statistic analysis.Results(1) In near accommodation, there were statistically significant increase in the thickness of anterior ciliary body, length of ciliary process and central lens depth. There were statistically significant decreases in width of ciliary process. (2)Decreased accommodation of human with ages. (3)Parameters of configuration had close correlation with each other, and it was also true in those of position.ConclusionsIn the process of near accommodation, ciliary body shifts forwards and inwards, ciliary process becomes tapered because the harmonious contraction of its circular and meridional muscle fibers, meanwhile decreased accommodation of hu- man with ages. This is consistent with the classical relaxation mechanism of accommodation described by Helmholtz. UBM is a new noninvasive method for real- time studying of the ciliary body changes in far-near accommodating human eyes in vivo.