Eyes - trachoma

Trachoma is a bacterial infection of the eye that can cause serious complications, including blindness. It is caused by the bacterium Chlamydia trachomatis and is sometimes known as sandy blight.

A preventable disease linked to hygiene#

Trachoma is a preventable disease linked to poor personal and community hygiene, and it is often associated with poverty. A lack of facial cleanliness is the main factor that allows the infection to spread. A single episode usually resolves on its own over a month or two and leaves little or no lasting impact. It is repeated infection that causes harm: a person may need around 150 to 200 episodes of infection and re-infection to sustain inflammation long enough to cause the severe scarring and in-turned eyelashes that lead to blindness.

Where trachoma occurs#

More than 40 developing countries, particularly across parts of Africa and Asia, are affected by trachoma, especially in rural areas where hygiene tends to be poor. Many countries have eliminated trachoma in recent years following improvements in living conditions.

During the 20th century there was considerable improvement in living standards in many parts of the world. Separate rooms for sleeping, running water and proper sewerage meant that trachoma disappeared from most high-income settings. It can persist, however, in remote and disadvantaged communities where these conditions are not yet in place.

How trachoma is spread#

Trachoma is transmitted by:

• direct contact, such as touching infected eye or nasal secretions
• indirect contact, such as touching contaminated items like towels, sheets, blankets or clothing

Signs and symptoms#

Signs and symptoms usually begin within 5 to 12 days of infection and may include:

• eye irritation, redness and discharge (conjunctivitis)
• swelling of the eyelids
• inflammation inside the upper eyelid
• lymphoid follicles (small lumps caused by an immune-system reaction) and scarring

Some people with trachoma have no symptoms, and the condition may go unrecognized unless it is specifically looked for. Without treatment, recurrent infection and inflammation can cause corneal scarring and eyelid deformities.

Complications#

A common late complication is eyelid inversion (entropion), where the lashes turn inwards (trichiasis) and continually rub against the cornea. This irritation can lead to corneal scarring and, over the long term, vision loss and blindness. Abnormal growth of blood vessels across the cornea can also occur.

Risk factors#

Particular risk factors include:

• inadequate personal hygiene, especially a dirty face in children
• limited understanding of the importance of facial and environmental cleanliness
• a poor or unsafe water supply
• inadequate housing and a lack of safe, functional bathrooms
• crowded living conditions, such as children sharing the same bed
• young age, since the infection is more common among preschool children

Diagnosis#

Diagnosis is normally made by clinical examination, including an eye examination in which the eyelid may be everted (flipped) to look for follicles and scarring. An eye swab may be taken for laboratory testing.

Treatment#

Treatment depends on the severity of the condition and may include:

• Antibiotics. A single oral dose of an antibiotic (azithromycin) is the first-line treatment in uncomplicated cases. It kills the bacteria so the body’s natural healing can repair the eye. Antibiotics are usually given to all members of a household where trachoma is found, and where infection is widespread the whole community may need to be treated. Treatment may need to be repeated every 6 to 12 months.
• Surgery. Surgery is used in older people to correct the eyelid deformity and turn the in-turned eyelashes outwards, away from the cornea.

Prevention#

A clean face and a clean environment, with no visible secretions from the eyes or nose, are the main strategies to combat trachoma. Control programs widely follow the World Health Organization’s SAFE strategy, which stands for Surgery, Antibiotics, Facial cleanliness and Environmental improvement. Proper implementation of the full SAFE strategy has significantly reduced trachoma in many communities, though prevention in remote, under-resourced areas remains challenging.

Key points#

• Trachoma is caused by the bacterium Chlamydia trachomatis
• This preventable disease is linked to poor hygiene and is often associated with poverty
• A lack of facial cleanliness is the main factor that allows the infection to spread
• It still occurs in some remote and disadvantaged communities
• Prevention relies on a clean face and a clean environment, following the WHO SAFE strategy

Where to get help#