Ocular Tuberculosis

Ocular tuberculosis (TB) is a clinical disease caused by or associated with Mycobacterium tuberculosis (MTB). MTB has various modes of transmission and can infect virtually any ocular tissue. Much like syphilis' ability to mimic multiple skin conditions, ocular TB should be thought of as "the great imitator" of ocular pathologies. Choroidal tubercles were first anatomically described in 1855 and identified with an ophthalmoscope in 1867. A year after discovering the organism, MTB was identified in the eye in 1883. An autopsy study of miliary TB in 1950 even reported that eye examination exceeded chest radiography in diagnostic sensitivity. Since this time, TB has become increasingly rare in Western nations, and advancements in laboratory diagnostic tests have led eye examinations for choroidal tubercles to fall out of favor in current guideline recommendations. Globally, more than 1.7 billion people are estimated to be infected with TB. Additionally, MTB is the leading cause of death from a single infectious agent globally and the leading cause of death among persons living with human immunodeficiency infection. Recognition of ocular TB as a clinical manifestation of extrapulmonary TB is critical, as a timely diagnosis can lead to early initiation of antituberculosis therapy and prevent poor patient outcomes. Most cases of ocular TB are presumptive, as getting histological or microbiological evidence of infection is extremely difficult. Also, the ocular disease may be due to direct infection or an immune reaction to MTB. Uniform diagnostic criteria are lacking, and the interpretation of diagnostic modalities may vary globally. However, early detection and prompt management of cases with presumed ocular tuberculosis may lead to good outcomes.