Reversible visual loss caused by fibrous dysplasia.

Fibrous dysplasia is a developmental anomaly of bone, often affecting the facial bones. We treated a patient who had fibrous dysplasia involving the right maxillary and sphenoid bones. The patient had a sudden loss of visual acuity to R.E.: counting fingers. Visual fields demonstrated a central scotoma, and retrobulbar neuritis was diagnosed. When vision failed to improve spontaneously, however, radiologic studies were performed. These showed compromise of the optic canal by bony proliferation and an apparent mucocele at the orbital apex. Surgical exploration disclosed fibrous dysplastic bone and a cystic structure overlying the optic nerve. Successful surgical excision of the cyst and debulking of the fibrous dysplasia resulted in visual acuity returning to R.E.: 20/25.