Current concepts of cerebrospinal fluid dynamics and the translaminar cribrosa pressure gradient: a paradigm of optic disk disease.

Modern advances in measuring and studying cerebrospinal fluid dynamics have furthered our understanding of intracranial pressure and its pathophysiological effects on the eye. In particular, the cerebrospinal fluid pressure and composition within the optic nerve subarachnoid space are key factors in diseases of the optic disk. Intracranial pressure and intraocular pressure establish a pressure gradient across the lamina cribrosa. Alterations in this translaminar cribrosa pressure difference induce structural deformations in the lamina cribrosa manifested clinically by the appearance of optic disk edema or optic disk cupping. Much has been learned about papilledema (i.e., optic disk edema due to elevated intracranial pressure) from clinical observations and studies on patients with idiopathic intracranial hypertension. Furthermore, optic nerve subarachnoid space hydrodynamics and translaminar cribrosa pressure difference are postulated to contribute to the pathogenesis of optic disk edema observed in spaceflight-associated neuroocular syndrome. Recently, a substantial body of literature has accumulated suggesting low intracranial pressure may be a risk factor for the development of glaucomatous optic disk cupping within the context of the translaminar cribrosa pressure difference and posterior scleral biomechanics.