Report of a case, in a male, white, 48 years old man, who presented a blindness of inferior half of visual fields, since one year before his admission in the hospital. The disease progressed slowly after a maxillar and frontal sinusotomy was performed. Several complementary tests were normal. Wassermann reactions were normal. Ophthalmologic examination revealed in superior half of papillae, in both eyes, a severe atrophy and edema in their inferior halves. Other neurological functions and clinical examination were normal. Ventriculography with lipiodol showed radiological signs of optochiasmatic arachnoiditis. Operation showed a severe arachnoiditis in chiasmatic region, which compressed optic nerves and chiasma. After intervention, successive ophthalmologic examinations revealed a considerable improvement of visual acuity, in both eyes, and a moderate increase of visual fields. The probable etiologic causes of this kind of meningeal reaction are discussed.
