Ocular tuberculosis-diagnostic difficulties and therapeutic features
Tuberculosis (TB) is an infection caused by Mycobacterium tuberculosis, which can cause disease in multiple organs throughout the body, including the eye. The term “ocular Tuberculosis ” describes an infection, tuberculosis species that can affect any part of the eye (intraocular, superficial, or surrounding the eye), with or without systemic involvement. “Secondary ocular TB” is defined as ocular involvement as a result of seeding by hematogenous spread from a distant site or direct invasion by contiguous spread from adjacent structures, like the sinus or cranial cavity.
Majority of the patients are diagnosed with presumed ocular TB based on local epidemiology, consistent ocular phenotypes, and positive corroborating tests, such as purified protein derivative (PPD) skin test and/or interferon gamma release assays (IGRAs). Patients are commonly referred for initiating antitubercular therapy (ATT) based on the positivity of the immunologic test results, with no pathological findings on chest imaging and no active clinical signs of systemic disease.
Most patients with Ocular Tuberculosis have no other systemic manifestations of the disease. Delay in diagnosis or treatment can lead to loss of vision. In general, recurrent idiopathic uveitis, which does not respond to conventional therapy, may be suggestive of tuberculous etiology. The eye examination should be routinely considered in patients with suspected or proven TB. Early diagnosis and prompt treatment of Ocular Tuberculosis can prevent serious complications and loss of vision.
Recent advances in technology established the role of multimodal imaging in the diagnosis and management of OTB. Detecting a phenotype suggestive of OTB is essential to make a presumptive diagnosis, and monitoring the course of the disease plays a key role in the correct therapeutic management. Techniques, such as FA, ICGA, and OCT, together with novel imaging modalities, including FAF, ultrawide field (UWF) imaging, and optical coherence tomography angiography (OCT-A), supplement each other and provide useful information on the natural course and therapeutic response of the disease.
