Eye signs for the neurologist in the Intensive Care Unit

The eyes are a window to the brain' is a maxim that holds true especially in the intensive care setting. Recognising specific eye signs aids rapid decision-making regarding diagnosis or prognosis. Eye signs play a pivotal role in intensive care for the neurologist.

Eye signs have long been considered the best clinical clue for assessment of a comatose patient. In critically ill patients, the recognition of brainstem involvement hinges primarily on eye signs. The ability to recognise and interpret these signs goes a long way towards ensuring proper care of neurological illness in intensive care units.

In this article we enumerate the various signs to be assessed in the ocular and periocular structures. We look at the various types of nystagmus and abnormal eye movements which help to localise lesions in the brainstem. This will aid better diagnosis and prognostication. We categorise eye signs as Category 1 or 2 according to whether they are periorbital and ocular signs or oculomotor abnormalities. Category 2 signs are further sub-classified into Category 2a - common and Category 2b - uncommon.

Clinical anatomical correlation of specific signs such as ocular dipping has yet to be elucidated. Research that looks into specific eye signs may help with better anatomic correlation and localisation of lesions.