Computing three-dimensional eye position quaternions and eye velocity from search coil signals

Area of Science:

• Ophthalmology
• Neuroscience
• Biomedical Engineering

Background:

• Traditional methods like Fick coordinates have limitations in representing eye rotations.
• Quaternions offer a mathematically robust framework for describing 3D rotations.
• Understanding eye movements is crucial for diagnosing neurological and visual disorders.

Purpose of the Study:

• To present algorithms for computing eye position and angular velocity using quaternions.
• To demonstrate the advantages of quaternions for analyzing eye movements.
• To establish a reliable method for locating the primary eye position.

Main Methods:

• Utilizing two search coils in two or three magnetic fields to collect eye movement data.
• Developing algorithms to compute eye position quaternions from recorded signals.
• Calculating eye angular velocity directly, avoiding differentiation of position signals.

Main Results:

• Quaternions provide efficient computations and a simple representation of Listing's law.
• The proposed algorithms accurately compute eye position and angular velocity.
• Differentiation of eye position signals results in inaccurate velocity estimates.

Conclusions:

• Quaternions are a superior method for representing and analyzing eye rotations.
• The developed algorithms offer a reliable tool for quantitative eye movement analysis.
• This approach enhances the understanding of binocular vision and oculomotor control.