Effects of schlemm’s canal expansion: Biomechanics and migs implications

Abstract

Objective: To evaluate the change of biomechanical properties of the trabecular meshwork (TM) and configuration of collector channels (CC) by high‐resolution optical coherence tomography (HR‐OCT) induced by Schlemm’s canal (SC) dilation. Methods: The anterior segments of two human eyes were divided into four quadrants. One end of a specially designed cannula was placed in SC and the other end connected to a perfusion reservoir. HR‐OCT provided three‐dimensional (3D) volumetric and two‐dimensional (2D) cross‐sectional imaging permitting assessment of the biomechanical properties of the TM. A large fluid bolus was introduced into SC. Same‐sample, pre and post deformation and disruption of SC and CC lumen areas were analyzed. Results: Morphologic 3D reconstructions documented pressure‐dependent changes in lumen dimension of SC, CC, and circumferential intrascleral channels. 2D imaging established volumetric stress‐strain curves (elas-tance curves) of the TM in quadrants. The curves of TM elastance shift to the right with an increase in pressure‐dependent steady‐state SC area. After a bolus disruption, the SC area increased, while the CC area decreased. Conclusion: Our experimental setup permits the study of the biomechanical properties of TM by examining elastance, which differs segmentally and is altered by mechanical expansion of SC by a fluid bolus. The study may shed light on mechanisms of intraocular pressure control of some glaucoma surgery.