An introduction to trichiasis
Trachomatous trichiasis (TT) is an advanced stage of trachoma. It is defined as having one or more eyelashes from the upper eyelid touching the surface of the eye. Evidence of recent removal of inturned eyelashes from the upper eyelid is also a sign of trichiasis. The World Health Organization recommends surgery to reduce the risk of sight loss from TT.
In 2016, an estimated 2.8 million people with trichiasis needed surgery to avoid blindness. Encouragingly, the number of people requiring management for TT has reduced from 7.6 million in 2002 to 2.5 million in 2019, a 68% reduction. However, we will not reach everyone who currently needs surgery until 2032, unless we increase the surgical rate across affected endemic communities.
Why do people get trichiasis?
Repeated infection with Chlamydia trachomatis causes severe inflammation of the conjunctivae. This, along with the response of the immune system to the infection, leads to irreversible changes within the fibrous connective tissue of the eyelid. Scars form on the tarsal plate and conjunctivae.
This scar tissue leads to changes in the eyelids (including reductions in the volume and composition of the tear film) and may pull the eyelashes inwards. Sometimes the scarring is so severe that the whole eyelid margin rolls inwards; this is known as entropion.
The eyelashes come into contact with the surface of the eye. This is trachomatous trichiasis (TT). If the in-turned eye lashes are central, they will scratch the cornea during blinking, which is both painful and sight threatening.
This step in the progression of trachoma disease can be succinctly captured as “scars today, trichiasis tomorrow.”
Eventually, the rubbing of the eyelashes damages the cornea leading to opacification (known as CO) which you can see in this eye with TT. Central corneal opacities impair vision.
Trachomatous trichiasis (TT) © Matthew Burton/LSHTM CC BY-NC-SA 4.0
Who is affected by TT?
The rate of progression from scarring of the conjunctiva to TT varies across different communities. Progression depends how endemic trachoma is in a community - ongoing episodes of inflammation of the conjunctiva is a major risk factor.
TT mostly affects older people. However, in some highly trachoma-endemic regions it is not unusual to find young children with TT. Across most settings, women are up to four times more likely than men to get TT, regardless of age.
How do we prevent blindness from TT?
We can improve access to, awareness and acceptance of, surgery for TT by selecting an appropriate procedure and using a trained team to deliver the surgical service at a community level.
The earlier management is provided, the better the outcome for preventing blindness and visual impairment from TT.
People with TT do not always come forward for treatment. There are many reasons, depending on setting and personal circumstances.
Each trachoma elimination programme needs to put a system in place that tries to understand why people don’t come for TT surgery in their setting. This will help to actively find, counsel and provide the best treatment (either surgery or sometimes epilation) to people with TT.
Nyakeira (young girl in South Sudan)
A few years ago my eyes started hurting me - they were tearing and sensitive to smoke and light. My eyelashes started touching my eyes in the sunlight, so I sit in the shade with the elderly while my friends go out to play. The most I could do was pound and grind cereals for my mother because I was nearly blind. None of my friends or family knew what to do about my eye pain. My mother prayed that I could get medical attention and I could only cry thinking about my hopeless future.
© London School of Hygiene & Tropical Medicine CC BY-NC-SA 4.0