Background. The magnitude of anterioaxial shift of the human ciliary muscle
during accommodation and its ceasing of ciliary function with advanced age
are still unknown.
Patients and methods. A total 105 patients (aged 10-91 years) were examined
by high-resolution ultrasound biomicroscopy during disaccommodation and vo
luntary accommodation. Accommodative changes in the total area of the cilia
ry muscle and in the outer contour were quantified with a specially develop
ed software program for automatic contour determination.
Results. A significant anterior shift independent of age was observed in th
e total area of the ciliary muscle and defined points on the outer contour
of the muscle in the range of 56-121 pm, while the inward displacement was
less obvious. A decrease in the magnitude of configurational changes during
accommodation was observed with age.
Conclusion. The new software program could be useful in further investigati
ons of the accommodative process and evaluation of the potential causes of
presbyopia.