A persistent eye infection that causes damage to the cornea, the transparent front part of the eye
Trachoma is a serious, persistent eye infection that causes permanent scarring of the cornea, the transparent front part of the eye. Although rare in developed countries, trachoma is one of the world’s main causes of blindness. It affects about 400 million people, of whom about 6 million are blind.
Trachoma is due to the bacterium Chlamydia trachomatis, which is spread to the eyes by direct contact with contaminated hands or by flies. Trachoma is common in poor parts of the world, particularly in hot, dry countries that have poor sanitation and limited water supplies. Overcrowding encourages the spread of the trachoma infection.
To avoid becoming infected in a high-risk area, you should wash your hands and face regularly and avoid touching your eyes with dirty fingers.
Initially, trachoma causes inflammation of the conjunctiva, the membrane that covers the white of the eye and lines the eyelids (see Conjunctivitis). Later symptoms include:
Thick discharge from the eye that is affected.
Redness of the white of the eye.
Gritty sensation in the eye.
Over time, repeated episodes of trachoma can cause scarring on the inside of the eyelids. The scars may pull the eyelids inwards and cause the eyelashes to rub against the delicate cornea (see Entropion). Left untreated, the condition can lead to blindness.
In the early stages, trachoma is treated with antibiotic eyedrops or ointment (see Drugs acting on the eye). If trachoma has caused the eyelids to turn inwards, an operation may be needed to prevent the eyelashes from rubbing against the cornea. If the cornea has become scarred, sight may be restored by an operation called a corneal graft, in which a cornea from a donor is used to replace the scarred one.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.