Ocular ultrasound evaluation of optic nerve sheath diameter in military environments.

In this letter to the Editor, we would like to comment on the article by Betcher et al., concerning the possibility of teaching military trainees to obtain accurate optic nerve sheath diameter measurements, using a brief didactic and a hands-on training session. In particular, this letter notes the importance of the measurement of optic nerve sheath diameter in detecting the eventual elevated intracranial pressure following traumatic brain injury, highlights several limitations in the use of B-scan for such a purpose and suggests a more accurate evaluation with the standardized A-scan.