Trachoma is a type of bacterial eye infection. The condition is a leading cause of premature blindness worldwide, although it's now rare in developed nations, such as the UK.
How trachoma is 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 eye discharge produced by an infected person, or by contact with contaminated objects, such as towels and clothes.
Flies can also spread the infection. In the developing world, flies are one of the main ways that trachoma is spread.
Due to the fact that trachoma is so easily spread, many people are repeatedly infected and the risk of blindness increases with each infection.
Read more about what causes trachoma
Who is affected by trachoma?
Trachoma is a disease directly related to poverty. Trachoma was common during the 19th century, but due to improvements in health and hygiene, the condition is no longer a problem in England and the rest of the developed world (with the exception of some Aboriginal communities in Australia).
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 and the Middle East.
It's estimated that more than 80 million people have an active trachoma infection and 1.3 million people are blind as a result of repeated trachoma infections.
Trachoma is most common in children who are 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.
Read more about the risk factors for trachoma.
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 for trachoma is focused on the community rather than on the individual.
The World Health Organization (WHO) has recommended a community-focused treatment plan called SAFE. This stands for:
- Surgery - to repair any damage to the eyelids and eyes
- Antibiotics - a community-wide treatment programme to reduce the number of people who are carrying the Chlamydia trachomatis bacteria
- Facial cleanliness - where members of the community, particularly children, are encouraged to wash their face frequently
- Environmental improvements, such as constructing a well to provide clean, fresh water or having properly dug latrines to reduce the amount of flies in the community
The aim of the World Health Organisation (WHO) is to eliminate trachoma everywhere in the world by 2020. Read more about WHO-led initiatives to prevent blindness and visual impairment.
Symptoms of trachoma
The initial symptoms of trachoma include:
- mild irritation of the eyes
- a discharge of pus and/or mucus from the eyes
If a person has repeated trachoma infections, their symptoms can become more severe. Symptoms caused by repeated infection include:
- 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). 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.
Causes of trachoma
Trachoma is caused by bacteria called Chlamydia trachomatis, which is a similar type of bacterium to the one that causes the sexually transmitted infection, chlamydia.
The bacteria cause the follicles in the eyelids to become inflamed (red and swollen). Follicles are small sacs in the skin from which the eyelashes grow.
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 results in a deformity of the eyelids, causing the eyelashes to turn inwards and scratch the surface of the eyes. The scratching causes the cornea (transparent layer at the front of the eye) to become scarred, which can result in a partial loss of vision, followed by a total loss of vision.
How trachoma is spread
After a person is infected by the bacteria, their eyes, and in some cases their nose, produce a discharge that contains the bacteria. The discharge can be spread to other people's eyes by:
- an infected person touching their eyes and then touching other people
- sharing clothes, bed linen, towels and flannels
- flies, which can transmit small droplets of the discharge to other people
Environmental risk factors
Trachoma thrives in hot, dry and dusty 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
- Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.
- Chronic usually means a condition that continues for a long time or keeps coming back.
- Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
Diagnosing and treatment of trachoma
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.
Due to the highly contagious nature of trachoma, an entire community will be treated to stop it from spreading.
The World Health Organization (WHO) recommends carrying out an initiative called 'SAFE'. 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.
Environmental changes and face washing
Regular face washing is very important because it removes the contagious discharge produced by the infection and reduces the chances of the infection being spread through physical contact and flies. However, people are often reluctant to wash their faces regularly if clean water is limited.
Therefore, environmental improvements usually focus on the following three factors:
- improving access to clean water
- improving access to washing facilities
- reducing the local fly population
Even simple improvements to an environment can help reduce the spread of trachoma. For example, digging latrine pits (toilets in the ground) can help to reduce the fly population.
As many of the countries affected by trachoma are very poor, much of the environmental improvement work is done by charities, voluntary organisations and other non-governmental organisations (NGOs), such as:
- Sightsavers International - a charity that's working to eliminate conditions that can cause blindness
- Water Aid - a charity that seeks to provide clean water and safe sanitation facilities to the world's poorest people
Both antibiotic lotions (topical antibiotics) and tablets (oral antibiotics) can be used to treat trachoma.
In communities where trachoma is widespread, it's usually necessary to treat the whole community to prevent re-infection. 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 once a year for three years.
Eyelid rotation surgery can be used in cases of trachoma where scarring to the eyelids is causing the eyelashes to turn inwards. During surgery, an incision is made in the upper eyelid and the eyelashes are rotated away from the cornea.
The surgery is relatively straightforward and it can be carried out under local anaesthetic (painkilling medication). The procedure only takes around 15 minutes to complete.
In cases of visual impairment, it may be possible to restore some vision by removing the damaged corneas and replacing them with transplanted corneas. However, access to this type of surgery is usually unavailable in places where trachoma is widespread.
Prevention depends on promoting:
- awareness to prevent the spread of infection,
- better social conditions,
- clean water, and
- better hygiene.
The World Health Organisation (WHO) is heading an international campaign to completely wipe out trachoma worldwide by 2020 with the Alliance for Global Elimination of Trachoma (GET 2020) and the SAFE strategy.
The SAFE strategy involves:
- Surgery for trichisis as a result of trachoma.
- Antibiotics to treat infection.
- Face washing to reduce the spread of infection.
- Environmental change through access to clean water and improved sanitation.
- Antibiotics are medicines that can be used to treat infections caused by micro-organisms, usually bacteria or fungi. For example amoxicillin, streptomycin and erythromycin.