Monitoring of slow deformations in laser tissue reshaping with optical coherence elastography

Strain mapping based on analysis of complex-valued signal of optical coherence tomography (OCT) is applied to monitor slow deformations of biological tissues (e.g., cartilage or cornea) subjected to thermo-mechanical reshaping by moderate heating with an IR laser. Insufficiently relaxed internal stresses may slowly distort the required tissue shape on a scale from minutes to hours with strain rate ~10
^-4
s
^-1
. We show the ability of the developed OCT method to monitor strains with uncertainly ~10
^-5
on ~10
²
s intervals sufficient for shape-stability verification in intra-operational preparation of cartilaginous implants.