Nocardiosis is an extremely rare, opportunistic, Gram-positive bacterial infection that has a high mortality rate in those patients who are immunocompromised in the presence of disseminated disease. We describe a case of an elderly lady being treated with high-dose corticosteroids for giant cell arteritis that presented with ischaemic optic atrophy. Subsequent deterioration was accompanied by the development of subretinal lesions. Further extensive evaluation discovered she had pulmonary nocardiosis with widespread dissemination. The case has several learning points, in particular: Subretinal abscesses maybe a harbinger of serious hitherto undiagnosed infection which portend a poor prognosis.Vital signs in the immunocompromised may appear to be normal in the presence of serious infection.