Ophthalmic manifestations of acoustic neurinoma

Acoustic neurinomas comprise 8% of all primary intracranial neoplasms. The authors reviewed 100 cases of pathologically confirmed acoustic neurinomas and compared tumor size, based on observations at operation, with findings on history and physical examination. Of the 100 patients, 36 had a decreased corneal reflex, 36 had nystagmus, and 8 had papilledema. Ninety-two percent of the patients with nystagmus had brainstem compression from tumor, and unilateral nystagmus when present was predominantly on gaze toward the side of the tumor. A positive correlation was found between tumor size and the presence of signs and symptoms. Tumors causing nystagmus were at least 2 cm in greatest dimension; those causing a diminished corneal reflex were at least 2.5 cm; and those causing subjective symptoms and papilledema were at least 4.0 and 4.5 cm, respectively.