1598 Correspondence / American Journal of Emergency Medicine 37 (2019) 1585-1599

References

1. Geske JB, Ommen SR, Gersh BJ. Hypertrophic cardiomyopathy: clinical update. JACC Heart Fail 2018 May;6(5):364-75.
2. Yusuf SW, Bathina JD, Banchs J, Mouhayar EN, Daher IN. Apical hypertrophic cardio- myopathy. World J Cardiol 2011 Jul 26;3(7):256-9.
3. Marian AJ, Braunwald E. Hypertrophic cardiomyopathy: genetics, pathogenesis, clinical manifestations, diagnosis, and therapy. Circ Res 2017 Sep 15;121(7): 749-70.
4. Nagueh SF, Bierig SM, Budoff MJ, Desai M, Dilsizian V, Eidem B, et al. American Society of Echocardiography clinical recommendations for multimodality cardiovascular im- aging of patients with hypertrophic cardiomyopathy: Endorsed by the American So- ciety of Nuclear Cardiology, Society for Cardiovascular Magnetic Resonance, and Society of Cardiovascular Computed Tomography. J Am Soc Echocardiogr 2011 May; 24(5):473-98.
5. Zeineh NS, Eles G. Images in clinical medicine. apical hypertrophic cardiomyopathy. N Engl J Med 2015 Nov 5;373(19):e22.
6. Marchesini M, Uguccioni L, Parisi R, Mattioli G, Terzi F, Olivieri R, et al. The role of car- diac magnetic resonance imaging in hypertrophic cardiomyopathy. Rev Cardiovasc Med 2016;17(1-2):57-64.

   Ultrasound and Optic neuritis

   In conclusion, we would like to remark that echography could look simple but, as all the other techniques, it requires skill and knowledge of the anatomy to get trustworthy and reproducible results [16,17].

   Financial support

   None.

   No conflicting relationship exists for any author.

   Palmiro Cornetta, MD

   Presidio Ospedaliero “Maria SS Addolorata“, ASL Salerno, Eboli,

   Salerno, Italy

   Giuseppe Marotta, MD Maddalena De Bernardo, MD, PhD

   Livio Vitiello, MD Nicola Rosa, MD?

   Department of Medicine, Surgery and Dentistry, “Scuola Medica Salernitana“, University of Salerno, Salerno, Italy

   ?Corresponding author at: Department of Medicine, Surgery and Dentistry, “Scuola Medica Salernitana”, University of Salerno, Via S.

   Allende, 84081, Baronissi, Salerno, Italy.

   E-mail address: [email protected].

   Dear Editor,

   We were really interested in the paper by Yee et al. concerning four patients with optic neuritis, diagnosed with ultrasound [1].

   The possibility to detect optic nerve sheath diameter (ONSD) in- crease in case of optic neuritis or Intracranial hypertension has been

   https://doi.org/10.1016/j.ajem.2019.02.001

   References

   28 January 2019

   widely proven [2] but we would like to comment on the way the mea- surements have been taken in this case report.

   We will avoid to comment on the use of B scan for such measure- ment, which is now well known to be subjective and not very reliable due to the so called blooming effect [3-7] and how better is the A scan technique for this purpose [8-13].

   We would like to put our attention on the table that have been pub- lished, which proves how important is the skill and the knowledge of ocular and orbital anatomy to make safe and repeatable diagnoses [14,15].

   In the introduction, the authors stated that “in order to measure the optic nerve sheath on-axis, the patients were instructed to look straight ahead and the ultrasound image view was verified to include the lens or iris; this was performed to prevent the possibility of measuring the optic nerve at an angle off midline”.

   In the table shown in the paper, only in the left eye of Case #1 the lens is visible in the scan, proving, in contrast with what the authors have stated, that all the other pictures are off-axis.

   Moreover, in our opinion, to include the lens in the image is correct but not sufficient, as the scanned plane should not only pass through the lens, but also through the optic nerve (ON) insertion. In this way, we are not only sure to be on axis, but we can also have reference points to measure the ONSD at the same 3 mm distance from the ON insertion.

   Unfortunately, the ON insertion is only visible in the right eye of pa- tient #3 and in the left eyes of patients #1 and #3. In patients #1 and #2, the images of the two eyes have been taken with different setting, mak- ing us wondering if the difference could have been due to the blooming effect. Furthermore, in patient #2, the distance where the measure- ments have been taken is not shown.

   In addition, in patient #4, the distance has not been taken at the center of the optic nerve, but laterally and, as the posterior wall of the eye is concave, the distance is obviously inferior to the one that would have been measured if it was put correctly at the center of the optic nerve.

   Yee NP, Kashani S, Mailhot T, Omer T. More than meets the eye: point-of-care ultra- sound diagnosis of acute optic neuritis in the emergency department. Am J Emerg Med 2019;37(1):177.e1-4.

7. Ossoinig KC. Standardized echography of the optic nerve. In: Till P, editor. Documenta ophthalmologica proceedings series vol 55, ophthalmic echography

   13. Dordrecht: Springer Netherlands; 1990. p. 3-99.

   De Bernardo M, Rosa N. Clarification on using ultrasonography to detect intracranial pressure. JAMA Ophthalmol 2017;135(9):1004-5.

8. Rosa N, De Bernardo M. Measurement of the optic nerve in a resource-limited set- ting. J Neurol Rural Pract 2017;8(2):310-1.
9. De Bernardo M, Rosa N. Transbulbar B-mode sonography in multiple scle- rosis: clinical and biological relevance. Ultrasound Med Biol 2018;44(2): 508.
10. De Bernardo M, Marotta G, Rosa N. Sonography of the optic nerve sheath diameter. J Ultrasound Med 2018;37(7):1845.
11. De Bernardo M, Rosa N. Transorbital sonography to evaluate optic nerve in hyper- tensive encephalopathy. J Stroke Cerebrovasc Dis 2018;27(4):1124.
12. Tenuta M, De Bernardo M, Rosa N. Comments on “Neuromuscular ultrasonography of Cranial nerves“. J Clin Neurol 2017;13(2):212-3.
13. De Bernardo M, Rosa N. Measuring optic nerve sheath diameter as a proxy for intra- cranial pressure. JAMA Ophthalmol 2018;136(11):1309-10.
14. Rosa N, De Bernardo M. ultrasound assessment of optic nerve sheath diameter in healthy volunteers. J Crit Care 2017;40:279.
15. De Bernardo M, Rosa N. Optic nerve sheath diameter measurement in pa- tients with idiopathic normal-pressure hydrocephalus. Eur J Neurol 2018; 25(2):e24.
16. De Bernardo M, Rosa N. Comment on ‘Invasive and noninvasive means of measuring intracranial pressure: a review’. Physiol Meas 2018;39 (5):058001.
17. De Bernardo M, Vitiello L, Rosa N. Optic nerve sheath diameter ultrasonog- raphy in differentiation of ischemic and hemorrhagic strokes. Am J Emerg Med 2019;37(7):1384-5.
18. De Bernardo M, Rosa N. Comment on “optic nerve sheath diameter ultra- sound evaluation in intensive care unit: possible role and clinical aspects in neurological critical Patients’ daily monitoring”. Biomed Res Int 2018; 2018:6154357.
19. Iaconetta G, De Bernardo M, Rosa N. Coronal axis measurements of the optic nerve sheath diameter. Am J Med 2017;36(5):1073.
20. Rosa N, De Bernardo M, Borrelli M, Filosa ML, Minutillo E, Lanza M. Reliability of the IOLMaster in measuring corneal power changes after hyperopic photorefractive ker- atectomy. J Refract Surg 2011;27(4):293-8.
21. De Bernardo M, Borrelli M, Mariniello M, Lanza M, Rosa N. Pentacam vs SP3000P specular microscopy in measuring corneal thickness. Cont Lens Anterior Eye 2015; 38(1):21-7.