In Vivo Human Corneal Shear-wave Optical Coherence Elastography

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Medical Imaging

Background:

• Accurate measurement of corneal biomechanical properties is crucial for clinical diagnosis and treatment.
• Existing methods for assessing corneal elasticity are limited.
• Optical coherence elastography (OCE) offers a promising noninvasive approach for evaluating soft tissue mechanics.

Purpose of the Study:

• To adapt dynamic optical coherence elastography (OCE) for in vivo, noninvasive clinical measurements of human corneal biomechanics.
• To characterize the propagation of mechanical waves in the cornea using dynamic OCE.
• To establish a method for determining corneal stiffness in a clinical setting.

Main Methods:

• Combined high-resolution phase-sensitive optical coherence tomography with microliter air-pulse stimulation for dynamic elasticity measurements.
• Measured submicron tissue deformations and surface wave velocity in 18 eyes of nine participants.
• Evaluated elastic wave propagation velocity in relation to intraocular pressure (IOP) and central corneal thickness.

Main Results:

• Demonstrated high sensitivity (0.24 nm) in measuring submicron corneal surface displacements (0.005 to 0.5 μm).
• Corneal elastic wave velocity ranged from 2.4 to 4.2 m/s (mean 3.5 m/s).
• Significant correlations were found between elastic wave velocity, central corneal thickness (r = 0.64), and IOP (r = 0.52).

Conclusions:

• Phase-sensitive OCT and air-pulse stimulation enable sensitive detection of elastic wave propagation in corneal tissue.
• This technique allows for in vivo determination of corneal stiffness.
• Further research will explore its utility in disease detection and monitoring clinical interventions.