Patients who undergo prompt intervention (i.e., surgery, hyperventilation, hyperosmolar therapy) after a new pupillary abnormality have improved recovery potential.Д¬ommon terminology employed in the clinical literature to describe the pupillary light reflex and pupil size includes вЂњunilateralвЂќ or вЂњbilateral nonreactive pupilsвЂќ, вЂњfixedвЂќ or вЂњdilated pupilsвЂќ, as well as вЂњbriskвЂќ, вЂњsluggishвЂќ, and вЂњnonreactiveвЂќ pupils. It has been shown that neurosurgeons have the tendency to triage patients into either conservative therapy or surgical evacuation of mass lesions, depending on the status of the pupils. In addition to herniation and third nerve compression, it has been shown through blood flow imaging that pupillary changes in the neurological intensive care unit (ICU) are highly correlated with brainstem oxygenation and perfusion/ischemia.ДЇurthermore, other investigators have used pupil size and reactivity as the fundamental parameters of more general outcome predictive models in conjunction with other clinical information such as age, mechanism of injury and Glasgow Coma Scale (GCS), and have correlated such models with the presence and the location of intracranial mass lesions.

Depressed light reflex and anisocoria have been associated with such phenomena, and they have been proposed as prognostic indicators of functional recovery after traumatic transtentorial herniation.

More specifically, the location of the pupillomotor nuclei in the dorsal midbrain and the efferent oculomotor nerve running from the midbrain to the superior orbital fissure is particularly important for assessing the onset of descending transtentorial herniation and brainstem compression. In the management and prognosis of severe traumatic brain injury (TBI), abnormalities of pupillary response or anisocoria (pupil size asymmetries) are often associated with neurological deteriorations, and they are correlated with poor neurological outcome. This makes the pupil size and the pupillary light reflex an important factor to be considered in many clinical conditions as described, for example, in the work of Loewenfeld.

Different neuroanatomical pathways are involved in the control of the pupil, and the integrity and functionality of these neurological pathways can often be ascertained through the analysis and interpretation of pupillary behavior.

Unequal pupil size icp