Depth-resolved Corneal Biomechanical Changes Measured Via Optical Coherence Elastography Following Corneal...

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Medical Imaging

Background:

• Corneal ectasia compromises corneal biomechanical properties.
• Corneal crosslinking (CXL) is a treatment to strengthen the cornea.
• Understanding depth-resolved changes after CXL is crucial for treatment efficacy.

Purpose of the Study:

• To evaluate depth-resolved changes in corneal biomechanical properties after CXL in ectatic corneas.
• To utilize optical coherence elastography (OCE) for in vivo assessment.

Main Methods:

• A prospective pilot study involving eyes with corneal ectasia.
• Custom high-speed swept source OCT system for imaging during applanation.
• OCE to track speckle displacements and calculate axial stiffness (k).
• Assessment of anterior (ka) and posterior (kp) stromal stiffness ratio (ka/kp).

Main Results:

• Four eyes (3 keratoconus, 1 post-LASIK ectasia) were analyzed before and 3 months after CXL.
• The mean ka/kp ratio increased from 1.03 ± 0.07 pre-CXL to 1.34 ± 0.17 post-CXL.
• All eyes showed at least a 20% increase in the ka/kp ratio.

Conclusions:

• Standard CXL protocol leads to preferential stiffening of the anterior corneal stroma.
• OCE demonstrates depth-dependent biomechanical changes in vivo after CXL.
• This study provides the first serial in vivo evidence of anterior stromal stiffening post-CXL.