Noncontact optical coherence elastography of the posterior porcine sclera in situ as a function of IOP

摘要

Recent work has shown that the biomechanical properties of tissues in the posterior eye have are critical for understanding the etiology and progression of ocular diseases. For instance, the primary risk for glaucoma is an elevated intraocular pressure (IOP). Weak tissues will deform under the large pressure, causing damage to vital tissues. In addition, scleral elasticity can influence the shape of the eye-globe, altering the axial length. In this work, we utilize a noncontact form of optical coherence elastography (OCE) to quantify the spatial distribution of biomechanical properties of the optic nerve, its surrounding tissues, and posterior sclera on the exterior of in situ porcine eyes in the whole eye-globe configuration. The OCE measurements were taken at various IOPs to evaluate the biomechanical properties of the tissues as a function of IOP. The air-pulse induced dynamic response of the tissues was linked to Young's modulus by a simple kinematic equation by quantified the damped natural frequency (DNF). The results show that the posterior sclera is not as stiff as the optic nerve and its surrounding tissues (～460 Hz and ～894 Hz at 10 mmHg IOP, respectively). Moreover, the scleral stiffness was generally unaffected by IOP (～460 Hz at 10 mmHg IOP as compared to ～516 Hz at 20 mmHg), whereas the optic nerve and its surrounding tissues stiffened as IOP was increased (～894 Hz at 10 mmHg to ～1221 Hz at 20 mmHg).