Abstract
Purpose :
Measuring the biomechanical properties of the cornea has become increasingly important to understand its health, detect disease, and evaluate therapies such as corneal collagen crosslinking (CXL). Here, we present a technique capable of mapping the stiffness of the cornea utilizing compression-based optical coherence micro-elastography of the cornea under various conditions, including before and after CXL in vivo.
Methods :
A ring based piezoelectric transducer induced low amplitude (< 5 µm) displacements in the cornea, which were then converted to strain using a vector-based technique. Experiments were conducted in in situ rabbit corneas in the whole globe configuration (N=3) under various intraocular pressures (IOP) (10, 15, 20, 25, and 30 mmHg) and before and after CXL. The IOP was controlled with a closed-loop system, and CXL was performed using the traditional “Dresden” protocol. In these samples, stiffness was further quantified by dividing the difference in IOP between the loaded and unloaded states (ΔIOP) by the calculated strain. In vivo experiments were also conducted on an anesthetized rabbit before and after CXL to evaluate the feasibility of the technique for live imaging. Here, the only strain was quantified.
Results :
In the in-situ samples, there was a significant difference in stiffness (ΔIOP/Strain) as a function of IOP (P = 0.037), and the stiffness increased by ~86% after CXL (P = 0.016). The strain decreased by ~85% after CXL in the in vivo rabbit cornea, which was significant (P < 0.001).
Conclusions :
Compression based optical coherence elastography of the cornea was able to detect the changes in corneal stiffness as a function of IOP and before and after CXL in an in situ as well in vivo rabbit cornea model. This technique may be useful for quantifying changes in corneal elasticity for disease detection or therapy monitoring.
This is a 2021 ARVO Annual Meeting abstract.