Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology
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Ultrasonography of the optic nerve sheath diameter (ONSD) is used for the non-invasive assessment of increased intracranial pressure (ICP). ONSD values are usually obtained by averaging the measurements of the two eyes, but asymmetric ONSD dilation is possible, leading to potentially inaccurate ICP estimation when using binocular averaging. In addition, few data are available about the asymmetry of the ONSD and the use of the maximum ONSD value between eyes for raised ICP detection. The aim of the study was to evaluate the interocular ONSD asymmetry in healthy subjects and patients with intracranial hypertension (IH) by ultrasonography and to investigate whether the maximum ONSD could be as useful as the binocular assessment. ⋯ Interocular ONSD asymmetry occurs both in healthy subjects and, more consistently, in patients with IH. Both binocular and maximum ONSD may be useful markers for increased ICP detection.