Low ICP and normal tension glaucoma: optic nerve damage due to barotraumatic factors, failure of CSF dynamics, or both? Response.

We replied to a letter by Wostyn et al. who contended that the pressure gradient with shear stress at the site of the lamina cribrosa may be accompanied by another mechanism, namely toxicity of non-recycled CSF around the optic nerve. We argumented our contention that a lowering of ICP underlies optic nerve damage in shunted normal pressure hydrocephalus and that those results support the role of changes in intraocular pressure and ICP gradient across the lamina cribrosa in the pathophysiology of NTG.