Bias in the measurement of optic nerve sheath diameter

According to the route of optic nerve approaching the globe, the oblique hypoechoic shadow running medially represents the exact measure of the optic nerve (Fig. 1). [...]the aforementioned method provides lower normal measurement of 3.5cm [2]. [...]the method of assessing ONSD and the interrater reliability of this highly operator-dependent diagnostic modality in predicting elevated intracranial pressure has yet to be validated to determine the prognosis and treatment. [...]as the authors implied, the chronicity of the increased ICP process may affect the correlation of ONSD sensitivity and specificity.