56 Ocular Tuberculosis

Tuberculosis (TB) infects one-third of the world population, and more than 80% of patients with active tuberculosis are HIV positive and at high risk of developing active disease. Intraocular TB constitutes a very small percentage of uveitis cases in North America and Europe (about 0.5%) but represents a much larger proportion in the developing world (over 30% in some studies in India). In the eye, TB may involve the choroid, retinal vessels, retinal pigment epithelium, outer retina, and vitreous and often two or more structures simultaneously. Clinical presentation includes granulomatous anterior uveitis, intermediate uveitis, and posterior or panuveitis. Routine testing for prior TB exposure includes tuberculous skin testing, an interferon-γ release assay (such as QuantiFERON-TB Gold), or chest X-ray or CT. Multimodal imaging, including optical coherence tomography, fluorescein angiography, fundus autofluorescence, indocyanine green angiography, and ultrasound, is useful as diagnostic tools and for long-term follow-up of the disease. The Center for Disease Control and Prevention recommends a four-drug anti-TB treatment regimen of isoniazid, rifampicin, ethambutol, and pyrazinamide for patients with active tuberculosis.