Indian Journal of Critical Care Medicine

Register      Login



Volume / Issue

Online First

Related articles

VOLUME 22 , ISSUE 9 ( 2018 ) > List of Articles


Sonographic Measurement of Optic Nerve Sheath Diameter: How Steep is the Learning Curve for a Novice Operator?

Gentle Sunder Shrestha, Binayak Upadhyay, Aanchal Shahi, K. C Jaya Ram, Pankaj Joshi, Bishesh Sharma Poudyal

Keywords : Learning curve, optic nerve sheath diameter, ultrasonography

Citation Information : Shrestha GS, Upadhyay B, Shahi A, Jaya Ram KC, Joshi P, Poudyal BS. Sonographic Measurement of Optic Nerve Sheath Diameter: How Steep is the Learning Curve for a Novice Operator?. Indian J Crit Care Med 2018; 22 (9):646-649.

DOI: 10.4103/ijccm.IJCCM_104_18

License: CC BY-ND 3.0

Published Online: 01-04-2015

Copyright Statement:  Copyright © 2018; The Author(s).


Background: Transbulbar sonography for measuring optic nerve sheath diameter (ONSD) is noninvasive bedside technique for detection of raised intracranial pressure. This study aims to evaluate the number of sonographic evaluations required for a novice operator to learn proper measurement of ONSD after a formal training and supervised scanning session. Methods: Three novice operators and one expert operator measured ONSD of 27 healthy volunteers using linear array transducer HFL38x (frequency range of 6—13 MHz) (MicroMaxx®; SonoSite, USA). In each eye, ONSD was measured three times by each observer and mean value was determined. Correlation coefficient was calculated between the novice and the experienced operator and in between the novice operators. Number of scans, after which the significant correlation developed between novice and the experienced operator and between the novice operators, was analyzed. Results: Cronbach's alpha was tested to evaluate the reliability of the values obtained from intra- and interobservations. For all 27 cases, the value of Cronbach's alpha was high: 0.80—0.99 for the right eye and 0.69-0.97 for the left eye. The mean interobserver variations were plotted on a graph which fluctuated largely in the first 17 cases but oscillated around 0.5—0.30 in the last 10 cases. Conclusion: Learning curve for novice operators to measure ONSD is steep and they can be taught to measure ONSD in healthy volunteers by sonography in supervised clinical session with an acceptable clinical precision and accuracy comparable to an experienced operator.

PDF Share
  1. Dubourg J, Javouhey E, Geeraerts T, Messerer M, Kassai B. Ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure: A systematic review and meta-analysis. Intensive Care Med 2011;37:1059-68.
  2. Shirodkar CG, Rao SM, Mutkule DP, Harde YR, Venkategowda PM, Mahesh MU, et al. Optic nerve sheath diameter as a marker for evaluation and prognostication of intracranial pressure in Indian patients: An observational study. Indian J Crit Care Med 2014;18:728-34.
  3. Bäuerle J, Lochner P, Kaps M, Nedelmann M. Intra — And interobsever reliability of sonographic assessment of the optic nerve sheath diameter in healthy adults. J Neuroimaging 2012;22:42-5.
  4. Ballantyne SA, O'Neill G, Hamilton R, Hollman AS. Observer variation in the sonographic measurement of optic nerve sheath diameter in normal adults. Eur J Ultrasound 2002;15:145-9.
  5. Bäuerle J, Schuchardt F, Schroeder L, Egger K, Weigel M, Harloff A, et al. Reproducibility and accuracy of optic nerve sheath diameter assessment using ultrasound compared to magnetic resonance imaging. BMC Neurol 2013;13:187.
  6. Soldatos T, Karakitsos D, Chatzimichail K, Papathanasiou M, Gouliamos A, Karabinis A, et al. Optic nerve sonography in the diagnostic evaluation of adult brain injury. Crit Care 2008;12:R67.
  7. Mayo P, Arntfield R, Balik M, Kory P, Mathis G, Schmidt G, et al. The ICM research Agenda on critical care ultrasonography. Intensive Care Med 2017;43:1257-69.
  8. Hansen HC, Helmke K, Kunze K. Optic nerve sheath enlargement in acute intracranial hypertension. Neuro Ophthalmol 1994;14:345-54.
  9. Hansen HC, Helmke K. Validation of the optic nerve sheath response to changing cerebrospinal fluid pressure: Ultrasound findings during intrathecal infusion tests. J Neurosurg 1997;87:34-40.
  10. Kristensen MS, Teoh WH, Graumann O, Laursen CB. Ultrasonography for clinical decision-making and intervention in airway management: From the mouth to the lungs and pleurae. Insights Imaging 2014;5:253-79.
PDF Share
PDF Share

© Jaypee Brothers Medical Publishers (P) LTD.