Techniques for imaging optic disc vasculature in glaucomatous optic neuropathy: A review of the literature
Aubert, T., R. Lecoge, P. Bastelica, M. Atlan, M. Paques, P. Hamard, C. Baudouin, and A. Labbé
Journal Francais d'Ophtalmologie 48, no. 2, 104369 (2025)
Résumé: The anatomy and vasculature of the optic nerve head are complex and subject to numerous variations. The main risk factor for glaucomatous optic neuropathy is elevated intraocular pressure, but many other factors have been identified. A vascular component seems to play an important role in the pathogenesis and/or progression of glaucomatous optic neuropathy, either under the influence of ocular hypertension or as an independent risk factor, particularly as in normal tension glaucoma (NTG). Reduced ocular blood flow has been identified as a risk factor for glaucoma. Numerous instruments have therefore been developed to explore the vasculature of the optic nerve head and to try to better understand the changes in blood flow in the optic nerve in glaucomatous optic neuropathy. In this review, we provide an update on the various means of imaging the vasculature of the optic nerve head, from angiography to the most modern techniques with angiographic OCT and laser Doppler holography. Using the results found in glaucomatous optic neuropathies, we will explore the close link between reduced ocular blood flow and the development or progression of glaucoma. A better understanding of this pathophysiology opens the door to improved management of our glaucoma patients.
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Computation of leaky waves in layered structures coupled to unbounded media by exploiting multiparameter eigenvalue problems
Gravenkamp, H., B. Plestenjak, D. A. Kiefer, and E. Jarlebring
Journal of Sound and Vibration 596 (2025)
Résumé: We present a semi-analytical approach to compute quasi-guided elastic wave modes in horizontally layered structures radiating into unbounded fluid or solid media. This problem is of relevance, e.g., for the simulation of guided ultrasound in embedded plate structures or seismic waves in soil layers over an elastic half-space. We employ a semi-analytical formulation to describe the layers, thus discretizing the thickness direction by means of finite elements. For a free layer, this technique leads to a well-known quadratic eigenvalue problem for the mode shapes and corresponding horizontal wavenumbers. Incorporating the coupling conditions to account for the adjacent half-spaces gives rise to additional terms that are nonlinear in the wavenumber. We show that the resulting nonlinear eigenvalue problem can be cast in the form of a multiparameter eigenvalue problem whose solutions represent the wave numbers in the plate and in the half-spaces. The multiparameter eigenvalue problem is solved numerically using recently developed algorithms. Matlab implementations of the proposed methods are publicly available.
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