Modeling and measuring the biomechanical properties of eye coats

Increased intraocular pressure is an important risk factor for the development of glaucomatous optic neuropathy. Deformation in the optic nerve head, especially of the lamina cribrosa, seems to be closely related to ganglion cell death in glaucoma. For this reason, the mechanical response of ocular structures to an elevation in intraocular pressure has been studied using biomechanical models of the eye. Measurement of the pulsatile, heart-rate related movement of ocular structures can be helpful for the further development and improvement of these eye models and may help predict an individual's susceptibility to changes in intraocular pressure. The movement of ocular tissue is currently very difficult to assess with optical coherence tomography or other imaging methods, because the axial resolution of these methods is not sufficient for observing the time course of the pulsations. A novel method called low coherence tissue interferometry, which enables for the depth-resolved measurement of ocular fundus pulsations, has recently been introduced by the authors. Coupling of a pulse oximeter to the system and recording the pulse curve synchronously with the interference pattern enables for creating pulsation movies, which exhibit the movement of structures at different axial and transversal positions.