Noncontact Acoustic Micro-Tapping Optical Coherence Elastography for Quantification of Corneal Anisotropic...

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Materials Science

Background:

• Corneal biomechanics are crucial for ocular health and disease diagnosis.
• Current methods for measuring corneal elasticity are often invasive or lack in vivo accuracy.
• Noncontact and noninvasive techniques are needed for precise in vivo corneal property assessment.

Purpose of the Study:

• To demonstrate accurate in vivo measurement of corneal elastic moduli using noncontact and noninvasive optical coherence elastography.
• To quantify the anisotropic elastic properties of rabbit corneas in vivo.
• To explore the intraocular pressure (IOP)-dependence of measured corneal mechanical properties.

Main Methods:

• Noncontact dynamic acoustic micro-tapping optical coherence elastography (AµT-OCE) was used for in vivo rabbit cornea measurements.
• A nearly incompressible transverse isotropic (NITI) model was employed to reconstruct elastic moduli.
• Ex vivo destructive mechanical tests (tensile extensometry, shear rheometry) were performed for validation.

Main Results:

• Strong anisotropy of corneal elasticity was demonstrated in rabbits.
• In-plane Young's modulus (E) ranged from 20 MPa to 44 MPa.
• Out-of-plane shear modulus (G) ranged from 34 kPa to 261 kPa.
• Ex vivo OCE and destructive tests validated the AµT-OCE findings.

Conclusions:

• Noncontact AµT-OCE can noninvasively quantify in vivo corneal anisotropic elastic properties.
• The technique's accuracy and noninvasive nature support its potential for clinical translation.
• AµT-OCE may enhance diagnostics for ectatic corneal diseases and personalized eye care.