Overview
It often starts so mildly in early childhood that nobody notices, a bit of redness and irritation in the eye that clears up and comes back many times over the years. It is often only decades later, sometimes in someone’s thirties or forties, that the real damage becomes visible, and by then, some of it can no longer be undone.
Disease Summary
- Category
- Infectious Disease
- Cause
- Chlamydia trachomatis, a bacterium that infects the eye
- Transmission
- Direct contact with eye or nose discharge, contaminated hands, clothing, or bedding, and flies that have been in contact with discharge
- Body System
- Eyes
- Preventable
- Yes
- Curable
- Yes
Symptoms
Common Symptoms
Active infection is most common in young children and often causes mild, easily overlooked symptoms.
Redness and Irritation
The eye may appear red and feel irritated, similar to a mild case of conjunctivitis.
Watery Eyes or Discharge
Discharge from the eyes or nose is common during active infection and is also how the infection spreads to others.
Swollen Eyelids
Mild swelling of the eyelids can occur during active infection.
Mild Sensitivity to Light
Some discomfort in bright light can accompany the irritation and swelling.
Signs of Advanced Disease
These indicate that repeated past infections have caused lasting damage and need prompt specialist assessment to prevent further vision loss.
Eyelashes Turning Inward
Eyelashes that rub against the eyeball, known as trichiasis, cause constant pain and can scratch the cornea with every blink.
Cloudy or Scarred Cornea
Visible cloudiness over the coloured part of the eye can indicate corneal scarring, a leading cause of trachoma-related blindness.
Scarring on the Inner Eyelid
Visible white lines, bands, or sheets on the inner surface of the upper eyelid indicate scarring from repeated past infection.
Worsening or Permanent Vision Loss
Progressive difficulty seeing can indicate the cornea has been permanently damaged.
Diagnosis
Eyelid Examination
A healthcare worker examines the inside of the upper eyelid, gently turned outward, for follicles, inflammation, or scarring, the basis of the standard grading system used worldwide.
Trichiasis Assessment
A close examination checks whether any eyelashes are touching the surface of the eye.
Laboratory Testing
PCR testing can confirm active infection with the bacterium, though diagnosis in endemic communities is usually made through examination alone.
Laboratory Tests
Eyelid Examination and Clinical Grading
Uses the WHO simplified grading system (TF, TI, TS, TT, CO) to classify the stage of disease based on visible signs.
PCR Testing
Confirms active Chlamydia trachomatis infection, more often used for research and surveillance than routine individual diagnosis.
Slit-Lamp Examination
Allows closer assessment of corneal involvement in more advanced cases.
Treatment
Antibiotic Treatment
Azithromycin clears active infection effectively and is distributed through mass drug administration programmes in affected communities.
Surgery for Trichiasis
Corrects inward-turning eyelashes to stop them from further damaging the cornea. It prevents further harm but cannot reverse vision already lost.
Prevention
Support antibiotic treatment programmes
Mass distribution of a single dose of azithromycin in affected communities clears infection and reduces transmission.
Practise facial cleanliness, especially in children
Regularly washing children’s faces removes the eye and nose discharge that spreads the infection.
Improve access to water and sanitation
Better access to clean water for washing, and to sanitation facilities, reduces the environmental conditions that allow trachoma to spread.
Support surgical treatment for trichiasis
Corrective surgery for in-turned eyelashes prevents further damage to the eye in people with advanced disease.
Risk Factors
Higher Risk of Infection
These groups are more frequently exposed to trachoma in endemic communities.
- Young children, who are the main reservoir of infection in endemic areas
- Women, who are blinded up to four times more often than men, likely due to closer contact with infected children
Environmental Risk Factors
Conditions that make transmission more likely within a community.
- Limited access to clean water and sanitation
- Crowded households
- Presence of flies that spread eye and nose discharge
Geographic Risk
Where someone lives significantly affects their risk of exposure.
- Living in one of the remaining countries where trachoma is a recognised public health problem, mostly in poorer, rural areas of Africa and parts of Asia and the Middle East
Complications
Trichiasis
Repeated infection can scar the inner eyelid enough that eyelashes turn inward and rub against the eye with every blink.
Corneal Scarring
Constant friction from in-turned eyelashes can permanently cloud the cornea.
Irreversible Blindness
Advanced corneal scarring is a leading cause of preventable blindness worldwide.
When to Seek Medical Care
Eyelashes Rubbing Against the Eye
This needs prompt assessment for corrective surgery to prevent further damage to the cornea.
Cloudy or Scarred Appearance of the Eye
A visible change in the clarity of the eye’s surface should be assessed by an eye care provider.
Persistent Eye Redness or Discharge in a Child
Ongoing symptoms, especially in areas where trachoma is common, are worth having checked, even if they seem minor.
Progressive Difficulty Seeing
New or worsening vision loss should be evaluated promptly, since some damage from trachoma cannot be reversed once it occurs.
Prognosis
Excellent for Active Infection
A single dose of antibiotic effectively clears active infection before lasting damage occurs.
Cumulative Risk With Repeated Infection
Years of repeated infection, most often starting in early childhood, are what eventually cause scarring and vision loss.
Vision Loss Is Usually Permanent
Once the cornea has been damaged by trichiasis, resulting blindness or visual impairment is difficult to reverse, which is why prevention matters more than late treatment.
Differential Diagnosis
Bacterial or Viral Conjunctivitis
Causes similar redness and discharge but does not lead to the same pattern of scarring seen in trachoma.
Allergic Conjunctivitis
Can cause similar redness and irritation but is linked to allergies rather than infection, and does not scar the eyelid.
Vitamin A Deficiency
Another significant cause of preventable blindness in some of the same regions, though it affects the eye differently.
References
World Health Organization (WHO)
World Health Organization fact sheet on trachoma transmission, symptoms, distribution, and the SAFE elimination strategy.
WHO: Diagnosis of Trachoma
WHO’s detailed guidance on the simplified grading system used to diagnose and stage trachoma.
StatPearls (NCBI Bookshelf)
Clinical reference detailing the trachoma grading system, diagnosis, and management.
Frequently Asked Questions
Is trachoma contagious?
Yes. It spreads through direct contact with eye or nose discharge, contaminated hands, clothing, or bedding, and flies that have touched the discharge of an infected person.
Can trachoma be cured?
Active infection is easily cured with a single dose of antibiotic. However, scarring or vision loss caused by repeated past infections cannot be reversed, which is why early treatment matters.
Why does trachoma affect women more than men?
Women are blinded by trachoma up to four times more often than men, likely because of their closer, more frequent contact with infected children.
How is trachoma being controlled globally?
Through the World Health Organization’s SAFE strategy: Surgery for advanced cases, Antibiotics to clear infection, Facial cleanliness, and Environmental improvements like better water and sanitation access.