We would like to thank Dr Jonas for his interest in our article. He raises the interesting and valid question as to whether a rise in cerebrospinal fluid pressure (intracranial pressure [ICP]) during weight lifting would balance any rise in intraocular pressure (IOP).
An increase in jugular venous pressure leads to an increase in IOP and also to an increase in ICP. A correlation between ICP and IOP has been suggested in some small studies.1- 3 We have also long wondered whether low ICP could be a contributing etiologic factor in normal-tension glaucoma. Such a correlation is anatomically plausible because the cerebrospinal fluid space surrounds the optic nerve sheath up to the point where the optic nerve enters the orbit, and an elevation in ICP may thus be directly transmitted to the globe. Another mechanism includes a rise in ophthalmic venous pressure caused by an elevation in ICP, which would then be transmitted to the ocular fluids with a consequent rise in IOP.3 Posterior displacement of the lamina cribrosa secondary to elevated IOP is likely to be the initiating event in the cascade that results in ganglion cell death in glaucoma.4
Vieira GM, Ritch R. Intraocular Pressure During Weight Lifting—Reply. Arch Ophthalmol. 2008;126(2):287-288. doi:10.1001/archophthalmol.2007.38