This case study is one of the first ever reported examples of infection in a patient with anti-IFN-3 autoimmunity and demonstrates how overwhelming infection can sometimes present with visual symptoms. We report the case of a previously fit middle-aged patient presenting with painless loss of vision and loss of appetite. Examination showed choroidal abscess and a pan-uveitis, leading to admission for vitreous biopsy. Klebsiella pneumoniae was isolated both in the vitreous and in blood cultures. Subsequent investigation discovered a liver abscess which was treated with percutaneous drainage. Despite the administration of intravitreal antibiotics from the time of presentation, intravenous antibiotics and vitrectomy on the same day, the patient proceeded to need enucleation 19 days later, and now has only light perception in the remaining eye. The strong association between K. pneumoniae endophthalmitis and underlying liver abscess leads to a significant mortality rate. Early diagnosis is essential, with prompt aggressive treatment with antibiotics, but sadly the visual prognosis remains poor. In cases of suspected choroidal abscess, initiation of sepsis screen and immediate empirical treatment is vital to improve this prognosis. This patient had no significant past medical history, no known immunocompromise, was not diabetic and had no recent significant foreign travel. However, further immunological analysis demonstrated the presence of anti-IFN-3 antibodies, a hitherto under-reported potential cause of increased susceptibility to infection, and so cases of sepsis in previously healthy individuals should be considered for further immunology assessment.