Ocular tuberculosis appears when the bacteria Mycobacterium tuberculosis, which causes tuberculosis in the lung, infects the eye, causing symptoms such as blurred vision and hypersensitivity to light. This infection may also be known as tuberculosis uveitis, as it causes inflammation of the uveal structures of the eye.
This type of infection is more common in patients with HIV, in patients already infected with tuberculosis elsewhere in the body or in people who live in places without basic sanitation for the treatment of sewage and wastewater.
Ocular tuberculosis can be cured, however, treatment takes a long time and can last between 6 months and 2 years, with the use of antibiotics recommended by the ophthalmologist.
Symptoms of ocular tuberculosis
The main symptoms of ocular tuberculosis are:
- Blurred vision or decreased vision;
- Increased sensitivity to light;
- Redness in the eyes;
- Burning sensation in the eyes;
- Floaters;
- Headache.
These symptoms are not present in all cases and can vary greatly depending on the affected location, which is normally the sclera or uvea of the eye, and may affect one or both eyes.
These symptoms can often appear when the person has already been diagnosed with pulmonary tuberculosis and, therefore, it is important to inform the doctor, as it may be necessary to change the antibiotic used.
How to confirm the diagnosis
The diagnosis of ocular tuberculosis is made by an ophthalmologist through the evaluation of symptoms, health and tuberculosis history, in addition to a physical and ophthalmological examination, such as funduscopy, to check changes in the retina or optic nerve. See the main ophthalmological exams.
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To confirm the diagnosis of ocular tuberculosis, the doctor must take a sample of fluid from the eye, to be analyzed in the laboratory and confirm the presence of the tuberculosis. Mycobacterium tuberculosis.
Possible causes
Ocular tuberculosis is caused by infection with bacteria Mycobacterium tuberculosisthe same disease that causes pulmonary tuberculosis, causing inflammation in the eye, mainly affecting the uvea, which is part of the eye formed by the iris, ciliary body and choroid, resulting in uveitis.
Read too: Uveitis: what it is, symptoms and treatment
However, this type of tuberculosis can affect both the internal structures of the eye, as well as the eternal structures, such as the eyelids, eye socket, lacrimal gland, sclera or cornea, for example.
How transmission happens
Ocular tuberculosis can be transmitted by different routes, the main ones being:
- Direct ocular infection (primary ocular tuberculosis): the bacteria directly infects the eyes, through direct contact of the eyelid or conjunctiva with the Mycobacterium tuberculosis;
- Hematogenous spread (secondary ocular tuberculosis): it happens when the bacteria present in the lungs spread through the blood reaching the eye;
- Hypersensitivity reaction: occurs due to an immunological response in the structures of the eye after exposure to tuberculosis antigens.
Although there are three forms of transmission of ocular tuberculosis, the most common route is the hematogenous route caused by pulmonary tuberculosis. See also other types of tuberculosis and how transmission occurs.
How the treatment is carried out
The treatment of ocular tuberculosis is carried out in the same way as the treatment of pulmonary tuberculosis and, therefore, begins with the use of 4 medicines, which include rifampicin, isoniazid, pyrazinamide and ethambutol, for around 2 months.
Read too: 4×1 medicine for tuberculosis: what it is and how it works
After this time, the ophthalmologist advises using 2 of these remedies, generally for another 4 to 10 months, to ensure that the bacteria is completely eliminated from the body.
In some cases, corticosteroid eye drops may also be prescribed to relieve itching and burning symptoms during treatment.
How long does ocular tuberculosis treatment last?
The treatment of ocular tuberculosis lasts at least 6 months, being divided into two phases, using a combination of 4 antibiotics for 2 months, followed by another 2 antibiotics for 4 months. Understand how tuberculosis is treated.
Since the treatment takes time, it is very important to follow all the doctor’s instructions, so that the bacteria is eliminated and does not continue to develop, becoming resistant and difficult to eliminate.
Tuberculosis prevention
The best way to avoid contracting tuberculosis is to take the BCG vaccine, which is administered to newborns in the hospital shortly after birth.
Furthermore, other ways to prevent tuberculosis are to avoid close contact with infected people, avoid exchanging cutlery, brushes or any other object that could come into contact with other people’s saliva.
Read too: Transmission of tuberculosis: how to catch it and how to avoid it
