Interaction of vascular and biomechanical aspects of glaucoma

Abstract

Abstract Purpose In an attempt to understand some of the reasons why some optic nerves appear to be sensitive to IOP and others not, I will review studies describing the interaction between vascular and biomechanical factors in open angle glaucoma. Methods Studies using biomechanical modelling, epidemiologic data, measurements of ocular or systemic blood flow, measurment of peripheral vasospasticity, and measurement of ocular biomechanical parameters will be reviewed. Hypotheses will be presented regarding the interpretation of these data. Results Studies suggest that the optic nerves of vasospasctic patients may be more IOP‐sensitive than those of non‐vasospastic patients. Non‐invasive measurements of ocular blood flow suggest that this pressure‐sensitivity may be related to IOP‐sensitive optic nerve blood flow. Biomechanical modelling suggests that scleral and lamina cribrosa elasticity, axial length, and eye wall thickness contribute to optic nerve head stress and strain. Cross‐sectional clinical data supports the role of increased ocular elasticity in the susceptibilty of the optic nerve to glaucoma damage, especially in vasospastic patients. Some promising new avenues for research in this area will be presented. Conclusion There is increasing evidence that biomechanical and vascular ocular factors interact leading to an elevated susceptibilty of the optic nerve to glaucomatous optic nerve damage. Commercial interest