Quantitative compressive optical coherence elastography using structural OCT imaging and optical palpation to measure...

Area of Science:

• Biomedical Optics
• Materials Science
• Mechanical Engineering

Background:

• Optical coherence elastography (OCE) is an emerging technique for measuring material mechanical properties.
• Traditional methods for mechanical property assessment can be complex and require specialized equipment.
• Developing non-contact or minimally invasive methods for material characterization is crucial for various applications.

Purpose of the Study:

• To apply the principle of optical palpation within a compression OCE framework to determine the mechanical properties of soft contact lenses.
• To validate the accuracy and repeatability of this novel technique.
• To explore its potential for broader applications in material and tissue mechanical testing.

Main Methods:

• Utilized spectral domain optical coherence tomography (OCT) for structural imaging.
• Employed optical palpation with a compliant transparent material acting as a stress sensor.
• Automated boundary segmentation tracked material thickness changes during compression to calculate strain.

Main Results:

• Successfully measured the mechanical properties (Young's modulus) of soft contact lenses without a force sensor.
• Achieved high accuracy, with experimentally derived Young's modulus showing less than 6% difference from nominal values.
• Demonstrated excellent repeatability, with no statistically significant difference (p > 0.01) compared to manufacturer's data.

Conclusions:

• Optical palpation in OCE provides an accurate and repeatable method for measuring material mechanical properties.
• The technique eliminates the need for sophisticated electronics to capture stress, simplifying the measurement process.
• This approach holds significant potential for translation into clinical applications, including ex vivo and in vivo tissue mechanical testing.