Noncontact depth-resolved micro-scale optical coherence elastography of the cornea

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Medical Imaging

Background:

• Corneal elastography is crucial for diagnosing ocular diseases.
• Current methods may lack resolution or require contact.
• Noncontact, high-resolution techniques are needed for precise assessment.

Purpose of the Study:

• To develop and demonstrate a novel noncontact, depth-resolved, micro-scale optical coherence elastography technique for the cornea.
• To investigate the feasibility of using spectral analysis of corneal Lamb wave propagation for stiffness mapping.
• To assess the potential for quantitative measurement of corneal viscoelasticity.

Main Methods:

• Utilized shear wave imaging optical coherence tomography (SWI-OCT) combined with spectral analysis of corneal Lamb wave propagation.
• Employed a focused air-puff device for noncontact, localized corneal loading.
• Applied phase-resolved OCT detection for nano-scale sensitivity to low-amplitude deformations.
• Analyzed temporal deformation profiles to obtain depth-wise phase velocity of Lamb waves.

Main Results:

• Successfully demonstrated noncontact, depth-resolved micro-scale elastography of the cornea.
• Obtained phase velocity of Lamb waves at different depths, revealing depthwise stiffness distribution.
• Corneal stiffness variations correlated with structural features.
• Pilot experiments on ex vivo rabbit eyes confirmed the method's feasibility.

Conclusions:

• The developed SWI-OCT method provides high-resolution, depth-resolved elastographic assessment of the cornea.
• Spectral analysis of Lamb wave propagation enables quantitative stiffness mapping.
• The technique shows significant potential for diagnosing corneal diseases and measuring viscoelasticity.