Trachoma is a type of bacterial eye infection. The condition is a leading cause of preventable blindness worldwide, although it's now rare in developed nations such as the UK.
Trachoma usually first affects young children, causing mild irritation of the eyes and a discharge of pus and/or mucus from the eyes.
By adulthood, repeated trachoma infections can result in more severe symptoms, including:
- blurred vision
- eye pain, which is often severe
- sensitivity to light (photophobia)
- an intense feeling of itchiness in the eyes – this is caused by the eyelashes turning back onto the surface of the eye
As the condition progresses, the "turned in" eyelashes will begin to scar the cornea (the transparent layer at the front of the eye). This is known as trichiasis.
The scarring will cause a person's vision to become increasingly cloudy and, left untreated, it will eventually lead to a complete loss of vision.
What causes trachoma and how does it spread?
Trachoma is caused by a type of bacteria called Chlamydia trachomatis, which can be highly contagious.
Someone can become infected if they come into direct contact with the discharge produced from the eyes or nose of an infected person, or by contact with contaminated objects such as towels and clothes.
Flies can also transfer the bacteria from the discharge. In the developing world, flies are one of the main ways trachoma is spread.
Read more about what causes trachoma.
Who is affected by trachoma?
Trachoma is a disease directly related to poverty. Improvements in health and hygiene mean the condition is now rarely a problem in the UK and the rest of the developed world, although it has been in the past.
Nowadays, trachoma is usually only found in the very poorest communities – typically villages and slums in hot, dusty climates where hygiene levels are poor and access to water and sanitation is limited. The majority of trachoma cases occur in Africa, the Middle East and parts of Asia.
It's estimated that 150 million people in the world require treatment for trachoma and six million people are blind because of the condition.
Trachoma is most common in children between one and five years old. In adults, women are more likely than men to develop trachoma because they tend to be in closer contact with young children.
How is trachoma treated?
Trachoma is simple to treat. However, as people with trachoma tend to live in areas where the condition is widespread, the risk of re-infection is high. Therefore, treatment usually involves whole communities.
The World Health Organization (WHO) has recommended an initiative called "SAFE" to help manage and eliminate trachoma. This stands for:
- Surgery – to repair any damage to the eyelids and eyes
- Antibiotics – to treat the infection
- Facial cleanliness – to prevent the spread of the bacteria
- Environmental improvements, such as constructing a well to provide clean water – to reduce the risk of re-infection
Read more about treating trachoma.
Trachoma is caused by bacteria called Chlamydia trachomatis.
The bacteria cause the lining on the inside of the eyelids – known as the conjunctiva – to become inflamed (red and swollen).
A single infection does not pose any serious threat to the eyes, but repeated infections can cause extensive inflammation and scarring of the eyelids.
Extensive scarring causes the eyelashes to turn inwards and scratch the surface of the eyes. The scratching scars the cornea (the transparent layer at the front of the eye), which can result in a gradual loss of vision and blindness.
How trachoma is spread
The bacteria that cause trachoma are spread in the discharge that comes from the eyes, and in some cases the nose, of someone with the condition. The discharge can be spread to other people's eyes by:
- an infected person touching their eyes or nose and then touching other people
- sharing clothes, bed linen, towels and flannels
- flies, which can transmit small droplets of the discharge to other people
Trachoma bacteria thrive in environments where:
- there are high levels of overcrowding – for example, where all family members sleep in the same room
- there's limited access to clean water
- there's limited access to washing facilities, such as showers or baths
- there's a large fly population
- there's limited access to healthcare services
Trachoma can usually be diagnosed by visually examining a person's upper eyelids.
If there's any doubt, further tests can be carried out by taking a sample of discharge and testing it for the presence of the Chlamydia trachomatis bacteria.
The World Health Organization (WHO), which aims to eliminate trachoma by 2020, recommends using a community-focused initiative called "SAFE" to manage the condition. SAFE stands for:
- Surgery – to repair damage to the eye
- Antibiotics – to treat the infection
- Face washing – to reduce the spread of infection
- Environmental changes – such as providing access to clean water and suitable sanitation
Because trachoma is highly contagious, an entire community will usually need to be treated to stop it from spreading.
Face washing and environmental changes
Regular face washing removes the contagious discharge from the eyes and reduces the risk of the infection spreading through physical contact and flies. However, people are often reluctant to wash their faces regularly if clean water is limited.
Improving access to clean water and washing facilities and reducing the local fly population can help limit the spread of infection.
Much of this work is carried out by charities, voluntary organisations and other non-governmental organisations (NGOs), such as:
- Sightsavers – an international charity that's working to eliminate conditions that can cause blindness
- WaterAid – a charity that seeks to provide clean water and safe sanitation facilities to the world's poorest people
Both antibiotic ointments (topical antibiotics) and tablets (oral antibiotics) can be used to treat trachoma.
The WHO recommends that if 10% or more of the children in a community have trachoma, everyone in the community should be treated with antibiotics to prevent re-infection.
Surgery will be used in cases where scarring of the eyelids is causing the eyelashes to turn inwards. During surgery, a cut is made in the upper eyelid and the eyelashes are turned away from the cornea.
It's a relatively straightforward procedure carried out under local anaesthetic, and takes around 15 minutes to complete.
Where there is visual impairment, it may be possible to restore some vision with a cornea transplant. This involves removing the damaged corneas and replacing them with corneas from a suitable donor. However, access to this type of surgery is usually unavailable in places where trachoma is widespread.