Intracranial hypertension (ICH) is a common and serious complication in children admitted to pediatric intensive care units. It is primarily caused by traumatic brain injury but can also result from brain malformations, brain tumors, or neuro-meningeal infections. Rapid identification of ICH in acute settings is crucial to ensure prompt management and mitigate potential consequences, such as severe neurological sequelae or death. The assessment of the pupillary light reflex is one of the key clinical parameters used to identify ICH in children with neurological injuries. This clinical sign is correlated with neurological prognosis. During an episode of ICH, regardless of the underlying cause, the oculomotor nerve becomes compressed between the midbrain and the temporal lobe, leading to anisocoria (unequal pupil sizes) and loss of pupillary reactivity. Other factors, such as episodes of ischemia or hypoperfusion in the midbrain, can also contribute to decreased pupillary reactivity.