A-scan ultrasound in ophthalmology: A simulation tool

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Computational Simulation

Background:

• A-scan biometry measures axial length (AL) for intraocular lens (IOL) power calculation in cataract surgery.
• Inaccurate AL measurements can lead to significant post-surgical refractive errors.
• Understanding error sources in A-scan biometry is critical for improving surgical outcomes.

Purpose of the Study:

• To develop a versatile computational tool for simulating A-scan ultrasound applications in ophthalmology.
• To evaluate diverse error sources affecting A-scan biometry and cataract characterization.
• To assess the impact of simulation parameters on accuracy and computational feasibility.

Main Methods:

• Developed a simulation tool using the k-Wave Matlab toolbox with a user-friendly interface.
• Simulated ophthalmological applications including cataract characterization and biometry.
• Evaluated the impact of constant ultrasound speed assumptions and probe positioning errors on refractive outcomes.

Main Results:

• Constant ultrasound speed assumptions can introduce refractive errors up to 0.6 D.
• Probe positioning errors were found to have a lower impact, up to 0.11 D.
• Cataract characterization sensitivity to echo amplitudes varies with cataract type and severity.

Conclusions:

• The developed simulation tool effectively evaluates aspects of A-scan biometry and its associated error sources.
• Simulation accuracy is influenced by grid resolution, with trade-offs in computational time.
• The tool provides a versatile platform for research in ophthalmic ultrasound simulation.