Presumed ocular tuberculosis in the United Kingdom: a British Ophthalmological Surveillance Unit (BOSU) study

INTRODUCTION: Ocular tuberculosis (TB) is an extrapulmonary manifestation of mycobacterium infection that most commonly presents as uveitis. This is the first prospective incidence study of presumed ocular tuberculosis performed in the United Kingdom (UK). METHOD: New cases of ocular tuberculosis presenting to hospitals in the UK were prospectively ascertained between October 2016 and November 2017 with the aid of the British Ophthalmological Surveillance Unit (BOSU). Initial presentation data and 1-year follow-up data was collected using questionnaires. RESULTS: Forty-eight patients were recruited giving an overall incidence for ocular TB of 0.73 per million population per annum. The origin of birth for 71% of the patients was a non-UK country and 87.5% had their initial diagnosis of TB made by an ophthalmologist. The most common first line treatment was isoniazid, rifampicin, ethambutol and pyrazinamide which 71% of patients were treated with 60% of patients were commenced on a reducing course of oral steroids. At 1-year follow-up, 29 patients (83%) had complete resolution of active clinical signs. Mean best corrected visual acuity (BCVA) at presentation was +0.41 LogMAR(SD = 0.62), compared to +0.31 LogMAR (SD = 0.56) at 12-month follow-up. DISCUSSION: It is increasingly the responsibility of the ophthalmologist to diagnose ocular TB and although it remains a rare condition, consensus on diagnostic criteria and treatment is required. Increasing recognition and accessibility to gamma-interferon testing should enable earlier detection. Treatment with quadruple ATT treatment regimens for at least 6 months shows good clinical outcomes. However, it is still unclear whether steroid use is beneficial. Further large studies with longer follow-up would be warranted to answer these questions.