Bilateral Cortical Blindness Caused by Tentorial Herniation due to Brain Tumor

ABSTRACT

Two patients, one with glioblastoma multiforme (GM) in the right thalamus and the other with meningioma at the right frontal convexity, had suffered bilateral cortical blindness after transtentorial herniation. On one of those patients, bilateral cortical blindness had occurred due to acute obstructive hydrocephalus caused by GM and on the other patient, cortical blindness had developed after acute hemorrhage from meningioma. Bilateral occipital lobes of those patients showed signal change on the brain magnetic resonance image (MRI). There were no ophthalmologic abnormalities on fundoscopy and ophthalmologic examination. After recovery of consciousness, cortical blindness was detected in both patients, and during gradual recovery period, visual function was slowly recovered. The pattern of visual evoked potential (VEP) at 7 weeks and 12 weeks after herniation was normalized gradually. Cortical blindness due to herniation was reversible, even though the high signals of bilateral visual cortex still existed on MRI 16 months later in case 2.