Trachoma - Causes of 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

Environmental factors

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