Definition
Trachoma is an infectious disease that afflicts the eyes, caused by Chlamydia trachomatis, a microorganism that is localized at the level of the conjunctiva causing an inflammatory process with chronic evolution.
This gram-negative bacterium causes the onset of the disease, which is transmitted by direct contact with the infected person, in particular by contact with eyes, eyelids, nose, throat and eye secretions. The transmission of the infection can also occur through contaminated objects (such as clothing, handkerchiefs, towels, etc.) or by means of vectors such as flies.
Bacterial infection is very contagious and almost always affects both eyes.
The signs and symptoms of trachoma begin with a slight itching and irritation to the eyes and eyelids, and may progress to corneal opacity (blurred vision), eye pain and - in the absence of adequate treatment - permanent blindness.
The causative agent of the disease ( Chlamydia trachomatis ) is widespread globally, but is endemic (constantly present and frequent) in many poor areas of Asia, Africa, Central and South America, Australia and the Middle East. In fact, trachoma has a higher incidence in arid climates and in sandy regions, where it spreads also thanks to the socio-economic under-development and poor hygienic conditions.
Trachoma spread
- According to estimates by the World Health Organization (WHO), trachoma affects around 84 million people worldwide, of which 8 million have visual impairments. Africa is the continent where the incidence is greatest.
- Trachoma is the second most common cause of blindness (after cataract).
- Children are particularly susceptible to infections, however they manifest a slower course (the most severe symptoms can appear in advanced adulthood).
Symptoms
To learn more: Symptoms Tracoma
The penetration of Chlamydia trachomatis into the epithelium of the conjunctiva gives rise to an acute inflammatory process (incubation period: 5-12 days). This condition manifests itself with tearing, hyperemia (increase in blood in the area) and mucopurulent secretion (mucus or pus).
As the disease progresses, symptoms include photophobia (inability to tolerate light), corneal opacity (with blurred vision) and eye pain. Following the first contact with the pathogen, the course of the disease takes on a chronic course characterized by recurrent exacerbations.
The main stages of development (and the appearance of related symptoms) of trachoma are:
 | 1) Inflammation at the follicular level | Initial stage of infection. Whitish swellings appear on the conjunctival mucosa (called follicles, they contain lymphocytes due to reaction to Chlamydia trachomatis infection). |
 | 2) Intense inflammation | Highly contagious phase. The eye becomes irritated, with a thickening or swelling of the upper eyelid. |
 | 3) Appearance of eyelid scars | Repeated infections cause scarring in the inner eyelid (they appear as white lines). The eyelid margin can rotate towards the inner (entropion). An advanced cicatricial state can induce thickening at the level of the eyelid. |
 | 4) Trichiasi | The inner lining of the eyelid continues to deform. The eyelashes reverse their orientation and come into contact with the ocular surface, causing irritation of the cornea due to their rubbing. This condition is very painful. |
 | 5) Corneal opacity | The cornea is affected by inflammation, which becomes chronic and leads to opacity of the same. Secondary infection can lead to the development of corneal ulcers and finally, partial or total blindness. |
Trachoma, after years of recurrent infections, is characterized by cicatricial sclerosis of the conjunctiva, which causes the eyelid to retract. The phase of trichiasis is the one that presents the highest risk of evolution in irreversible blindness.
