A 58 year old patient with no family history of interest and a personal history of arterial hypertension controlled pharmacologically for 6 years and maxillary sinusitis of 10 days' evolution without specific treatment. He came to the emergency department for "loss and distortion of vision" in the left eye (OI) of several days' evolution. The maximum visual acuity in the right eye (OD) was 1 and in the OI 0.125, extrinsic and intrinsic ocular motility were normal, the slit-lamp study showed no pathology. Funduscopic examination in the OD was normal but in the OI there was a macular serous detachment extending to the superior and inferior temporal vessels, the optic nerve and the rest of the retinal parenchyma were unaltered. She reported a cat scratch on the thigh of her left leg two weeks before the loss of vision. Seven days after being examined by us, she developed painful erythematous lesions limited to the lower extremities compatible with erythema nodosum, which ulcerated within 20-25 days. The patient was referred to the internal medicine department for further investigation. The chest X-ray was normal, the paranasal sinus X-ray revealed a slight veiling in the left maxillary sinus. Serological studies: ANA, ANCA, antiphospholipid antibodies were normal. CMV, EBV, Rickettsia, Toxoplasma, HIV, Lyme and luetic serology were negative. Mantoux was also negative. Haemogram: Leukocytes 20,670, ESR 64 mm 1 h, CRP 16.4 mg/L. Serological levels of IgM against B. Henselae by ELISA were positive at a titre of 1:812. The patient was treated with ciprofloxacin 1 gram per day for 14 days. Four weeks after treatment the systemic picture started to return and the ophthalmologic picture resolved with the OI reaching visual acuity of unity.