Examination of the eye is a fundamental part of the evaluation of a patient with suspected systemic illness. The combination of a peculiar mixture of the ability to directly visualize the vasculature directly and the propensity for ocular structures or the neurological connexions of the eye to fall foul of systemic disease mean that the symptoms or signs relating to the eye are often the initial manifestation of serious systemic illness. As a consequence, expertise in the examination of the eyes became a major feature of clinical examination for physicians in the 19th and 20th centuries with numerous physical signs and eponymous syndromes relating to the eye in existence. Sadly, nowadays the examination of the eye is not always in the pantheon of the trainee in general medicine; the MRCP PACES examination no longer has a mandatory ocular examination (http://www.mrcpuk.org/PACES/Pages/PacesFormat.aspx), and routine fundoscopy through dilated pupils performed by a medical practitioner is no longer a regular component of diabetes clinical management in the UK (http://www.scotland.gov.uk/Resource/Doc/321699/0103402.pdf). However, careful examination of the eyes can often detect subtle findings that provide invaluable information to complement laboratory examinations and non-invasive imaging and allow for accurate interpretation of these results in complex clinical circumstances. A 51-year-old woman was admitted to hospital as an emergency for the investigation of dyspnoea and facial discomfort. Nine months prior to this presentation she had been diagnosed with breast carcinoma and had undergone a right-sided lumpectomy and axillary clearance. The tumour was ER positive and the patient was post-menopausal. She subsequently received loco-regional radiotherapy and systemic chemotherapy with good initial clinical response. There was no other personal medical history of note. In particular, she was a non-smoker with no history of cardiovascular disease, hypertension or diabetes. Two months prior to this admission, the patient had presented to her local …