Optical coherence elastography for evaluating customized riboflavin/UV-A corneal collagen crosslinking

Area of Science:

• Biomedical Optics
• Ophthalmology
• Biomaterials Science

Background:

• Keratoconus treatment involves UV-induced collagen cross-linking (CXL) to stiffen corneal tissue.
• Targeted CXL could enhance treatment efficacy for localized corneal degeneration.
• Assessing localized biomechanical changes in the cornea is crucial for treatment monitoring.

Purpose of the Study:

• To demonstrate optical coherence elastography (OCE) for spatially resolving corneal stiffness variations.
• To validate OCE's ability to differentiate between untreated and selectively treated corneal regions.
• To assess the biomechanical impact of collagen cross-linking (CXL) on corneal tissue.

Main Methods:

• Utilized phase-stabilized optical coherence tomography (OCT) to detect low-amplitude deformations induced by focused air-pulses.
• Employed damped natural frequency (DNF) analysis to generate 2D stiffness maps from air-pulse induced responses.
• Validated the technique on heterogeneous phantoms and in situ rabbit corneas with spatially selective CXL treatment.

Main Results:

• OCE successfully mapped transverse variations in corneal stiffness.
• The technique clearly distinguished between untreated and CXL-treated regions in rabbit corneas.
• Collagen cross-linking (CXL) increased the corneal damped natural frequency (DNF) by approximately 51%.

Conclusions:

• Optical coherence elastography (OCE) provides spatially resolved, noncontact assessment of corneal biomechanical properties.
• This method can effectively differentiate CXL-treated from untreated corneal areas.
• OCE holds potential for in vivo evaluation of corneal stiffness and treatment efficacy.