Monitoring accommodative ciliary muscle function using three-dimensional ultrasound

Area of Science:

• Ophthalmology
• Biomedical Imaging
• Anatomy

Background:

• High-resolution ultrasound is crucial for in-vivo anterior segment imaging.
• Characterizing the ciliary body and posterior iris requires advanced imaging techniques.
• Quantifying configurational changes in the ciliary body during accommodation is essential for understanding visual function.

Purpose of the Study:

• To develop a 3D high-resolution ultrasonic imaging technique for in-vivo characterization of the ciliary body and posterior iris.
• To demonstrate the benefit of this imaging technique in quantifying ciliary body configurational changes during accommodation.
• To assess individual ciliary muscle activity and its changes with accommodation.

Main Methods:

• Utilized a computer-controlled scanning device with a standard ultrasound biomicroscope for 3D imaging.
• Employed custom software for online data collection, analysis, and 3D reconstruction with VoxelView software.
• Obtained sequential ultrasound biomicroscopic images of the ciliary body region.

Main Results:

• The 3D presentation enabled in-vivo approximation and analysis of ciliary muscle contour changes during accommodation.
• Observed a mean shift of 0.13+/-0.06 mm in the ciliary muscle center of gravity towards the lens equator during accommodation.
• Noted interindividual variation and a slight decrease in this shift with age.

Conclusions:

• 3D ultrasound biomicroscopy effectively assesses ciliary muscle activity and ciliary processes in vivo.
• Improved muscle contour determination during accommodation using contour analysis tools.
• Demonstrated ciliary muscle activity in both young and presbyopic individuals, highlighting its relevance across age groups.