Neuro-ophthalmic complications of raised intracranial pressure, hydrocephalus, and shunt malfunction

The unique anatomic location of the visual sensory pathway and all the ocular motor nerves in the brain has made the ophthalmic system vulnerable to increased intracranial pressure. Neuro-ophthalmic complications caused by increased intracranial pressure range from loss of visual acuity, visual field defects, abnormal pupillary function, and optic disc swelling or atrophy to eye movement abnormalities, including diplopia with extraocular motility disturbances and dorsal midbrain syndrome. Although ophthalmic involvement is well known to occur with increased intracranial pressure, it is not widely appreciated how frequently it is the major clue or sometimes the only reliable clue to the diagnosis of elevated intracranial pressure, thus making the visual evaluation relevant to management of raised intracranial pressure. Ophthalmic signs caused by increased intracranial pressure can necessitate emergent neurosurgical intervention sometimes even before the radioimaging signs become evident. Furthermore, the detection of ophthalmological signs of raised intracranial pressure not only can facilitate an early diagnosis but also can guide the treatment of visual impairment caused by elevated intracranial pressure to preserve vision. This article reviews the common neuro-ophthalmic signs of increased intracranial pressure as a result of various processes, including venous thrombosis, tumors, hydrocephalus, and consequences of shunt malfunction.