Granulomatous optic neuropathy

G. B. Krohel, H. Charles and R. S. Smith

A 24-year-old woman was seen with painless, progressive, unilateral visual acuity loss, optic nerve swelling, and opticociliary shunt vessels. Results of a skull series and conventional tomography showed enlargement and erosion of the optic canal. In addition, computed tomography (CT) disclosed a thickened optic nerve consistent with optic nerve sheath meningioma. A preoperative diagnosis of granulomatous optic neuropathy was based on the presence of mild posterior uveitis, "snowball" opacities in the vitreous ("string of pearl" sign), and a slightly elevated angiotensin-converting enzyme level. A specimen from a biopsy by means of a craniotomy indicated granulomatous optic nerve involvement with chiasmal invasion. The systemic effects of steroids for six months resulted in a modest improvement of visual acuity and restoration of normal optic nerve structure on repeated CT.