Abstract
Purpose :
Assessment of corneal biomechanical properties is essential for detecting disease and monitoring corneal treatments. Optical coherence elastography (OCE) is a tool for measuring these mechanical properties, but assessment is typically performed by measuring the corneal response to some sort of external excitation. Here, we demonstrate how Heartbeat Optical Coherence Elastography (Hb-OCE) can be used to measure the cornea’s mechanical response to the natural heartbeat-induced ocular pulse in the in vivo model.
Methods :
An SD-OCT system in the common path configuration was used to measure the biomechanical properties of the cornea in two anesthetized rabbits. The first rabbit was kept as an untreated (UT) control, and the second had its cornea collagen crosslinked (CXL) using the standard Dresden protocol. OCT images were acquired at the apex of the applanated rabbit cornea while cardiac activity was measured concurrently. Corneal displacement over time was measured and translated to strain.
Results :
Strain fluctuations in the UT cornea shown mirror the cardiac activity (~4Hz heart rate) of the rabbit. The untreated cornea had a mean strain amplitude over 12 cycles of 3.07 ± 0.48 mε, and the CXL cornea had a mean strain of 0.87 ± 0.19 mε. There was a statistically significant difference between the corneas in each group. (p<0.05).
Conclusions :
We demonstrate how Hb-OCE may be useful to measure the biomechanical properties of the cornea using heartbeat as a passive source of displacement. Furthermore, we show how this technique can distinguish the stiffness difference between UT and CXL corneas. Future work will be geared toward developing noncontact Hb-OCE with a quantitative model of stiffness.
This is a 2021 ARVO Annual Meeting abstract.