Study of Laser-Induced Microdeformations of the Cornea Using Phase-Sensitive Optical Coherent Elastography

In many clinical cases, knowledge of the biomechanical properties of the cornea will allow for early diagnosis and also contribute to the success of treatment. The methods existing in the clinic characterize the biomechanical properties of the cornea as a whole, but do not give an idea of its local properties. One of the promising approaches to measure local changes in biomechanics is optical coherence elastography (OCE) based on
phase-sensitive optical coherence tomography (OCT). In this work, the OCE method, based on the registration of small tissue deformations under an applied load, showed that the appearance and propagation of mechanical waves due to laser exposure depend on the loading of the studied biological tissue due to its tension with the application of various intraocular pressures (IOP). An analysis of inter-frame differential OCT images showed that the width of the laser impact zone on the tissue increases with increasing of IOP. An analysis of the strain amplitudes depending on the IOP at a given point revealed a correlation with the IOP value and made it possible to fix the fluidity threshold for the sample under consideration in the given experimental geometry.