Optic nerve sheath diameter measured using magnetic resonance imaging and factors that influence results in healthy Chinese adults: a cross-sectional study

To the Editor:Identifying the increase in intracranial pressure(ICP)is very important in the management of neurosurgical and neurological disorders,because raised ICP is associated with poor outcomes such as brain herniation and death.Although the intraparenchymal or intraventricular invasive methods remain the gold standard for ICP measurement,they cannot be routinely employed because of the lack of an adequate number of neurosurgeons.In addition,because of contraindications(eg,blood coagulation disorders and severe platelet disorders)and complications(eg,infection and hemorrhage),the invasive approach is not always possible.[1]Therefore,accurate non-invasive methods are needed to estimate ICP in clinical practice.A large number of studies have shown that the optic nerve sheath diameter(ONSD)is an indirect marker of ICP,and that there is a linear relationship between the two parameters.[1,2]Therefore,ONSD and its accurate measurement methods are getting more and more attention from scholars.