A 65 old year woman was admitted to the hospital for a low back pain, a fever and an elevated sedimentation rate. Four months later she noted a progressive visual loss first affected the right eye (visual acuity: 6/10) and then the left (visual acuity : 6/10). Fundus examination showed a bilateral papilledema. CT Scan and MRI were normal. A lumbar puncture disclosed a lymphocytic pleocytosis (68 leukocytes/mm3), an increase in protein level (1,9 g/l) and oligoclonal bands. A serologic test for B. Burgdorferi was positive both in blood (1/64 degrees) and in cerebrospinal fluid (> or = 1/128). The patient was treated with intravenous ceftriaxone 2 g daily for 2 weeks. Fifteen days later the low back pain had disappeared and the CSF cellular count had decreased to 20 leukocytes/mm3. Seven months later, CSF was normal (2 leukocytes/mm3, protein level: 0.65 g/l.); Titer against B. Burgdorferi had improved to 1/160 in serum and 1/16 in CSF; visual acuity had improved to 8/10 on left, and was the same on right.