Introduction

Trichiasis is a common eyelid condition where the eyelashes grow in the wrong direction, i.e. toward the eye instead of outward. These misdirected lashes can rub against the surface of the eye, including the inner eyelids, cornea (the clear front part of the eye), and conjunctiva (the thin membrane covering the eye), which can cause irritation, scratches, and even damage to vision.¹

Some people are born with trichiasis due to a genetic condition in which certain eyelid cells fail to develop into oil-producing Meibomian glands. This form, known as congenital trichiasis, is inherited in an autosomal dominant pattern. Trichiasis can also be acquired later in life.¹

Infection is another major cause. Repeated infections with Chlamydia trachomatis can lead to trachomatous trichiasis, which can cause the eyelid to turn inward (entropion) and eventually result in scarring of the cornea and permanent vision loss.²

Other conditions that may cause abnormal eyelash growth and lead to trauma-induced trichiasis include ocular cicatricial pemphigoid, Stevens-Johnson syndrome, chemical burns, eyelid injuries, and chronic blepharoconjunctivitis.²

Trichiasis most often affects the lower eyelids, but when the lashes grow inward from the inner corner of the eye, it's known as medial canthal trichiasis.³ If left untreated, trichiasis can reduce vision and, in severe cases, lead to blindness.³

It’s important to note that trichiasis is different from involutional entropion, a condition in which the edge of the eyelid turns inward, causing the normally positioned eyelashes to rub against the eye. This is often referred to as pseudo-trichiasis or secondary trichiasis.⁴

The recognition of trichiasis goes back as far as the time of Hippocrates (460–370 BCE). Although he couldn't clearly define the condition, treatments were already being used, such as epilation (plucking out the lashes) and surgical procedures using a needle and thread to reposition the eyelids. Between the 1st and 7th centuries CE, several notable figures, including Dioscorides, Galen, Oribasios, and Aetius, also documented methods for treating trichiasis.

In more recent history, surgical correction techniques for trichiasis have significantly improved. In 1887, Van Millingen described a technique called intermarginal split lamella, which involves separating the eyelid into two layers and placing a graft (a piece of tissue) to help the lashes grow in the correct direction.⁵

Later, in 1986, Steinkogler introduced a method called split margin division, which involves removing the part of the eyelid that has the misdirected lashes and then using a small piece of skin (a skin flap) to cover the area.⁵

Wojno later described a technique where the eyelid is split along the grey line (the natural line on the edge of the eyelid), and the front part of the eyelid that contains the lashes is removed. The area is then covered using glue to hold the skin in place while it heals.⁵

While trichiasis may seem like a minor irritation, trauma-induced trichiasis, where eyelashes grow inward due to injury or damage to the eyelid, can seriously threaten eye health. The constant rubbing of lashes against the eye can cause corneal scratches and ulcers, and may even lead to blindness if left untreated. This condition often results from avoidable causes, such as physical injuries, chemical burns, or surgical complications.⁵

Understanding this condition is vital. By recognising its causes, symptoms, and treatment options, healthcare providers can reduce discomfort and help prevent lasting damage. This article highlights the importance of early diagnosis and treatment in preserving vision and overall eye health, emphasising how trauma-induced trichiasis can impact quality of life and why awareness is essential.

Causes of Trauma-Induced Trichiasis

Trichiasis is a condition where too many eyelashes grow in the wrong direction, toward the eye. This can be caused by inflammation, infections, or other eye diseases.³

Some common causes include:

• Blepharitis – a bacterial infection that leads to red, swollen eyelids and can cause the lashes to turn inward
• Entropion – a condition where the eyelid itself turns inward, making the lashes rub against the surface of the eye
• Epithelial damage – irritation caused when the eyelid and lashes rub against the eye's surface
• Herpes zoster eye disease – a viral infection (related to shingles) that can cause pain, swelling, and vision problems
• Eye injuries, such as burns or chemical exposure, can damage the eyelid and lash direction⁵
• Skin conditions, like Stevens-Johnson syndrome, which affects the skin and mucous membranes and may cause skin peeling and scarring, including around the eyes⁵

These conditions can cause the lashes to grow in abnormal directions, leading to discomfort, eye irritation, and even vision problems.³

While trichiasis itself is not contagious, some of the conditions that cause it are, especially infections.

One of the leading causes of blindness globally is trachomatous trichiasis.³ This is a severe form of trichiasis caused by trachoma, an eye infection caused by the bacterium Chlamydia trachomatis. Trachoma spreads easily from person to person, especially in places with poor sanitation and limited access to clean water.³

Pathophysiological mechanisms

In cases of trauma-induced trichiasis, injury or inflammation around the base of the eyelash causes the tissue to become distorted. As a result, the eyelash starts growing in the wrong direction, inward, toward the eye. In some scarring (cicatrising) disorders, the eyelid edge may begin to turn inward even before a full inward-turned eyelid (called cicatricial entropion) develops. However, in many cases like this, the overall shape of the eyelid remains normal.⁴

The eyelids play a crucial role in spreading tears evenly across the eye and protecting the surface of the eye from damage or infection. Structurally, the eyelid is made up of two main layers, called the anterior lamella and the posterior lamella.

These two layers are divided by the grey line, which is a natural line on the eyelid formed by a small muscle called the Riolan muscle, part of the pretarsal orbicularis muscle (a muscle that helps the eyelids close).

• The anterior lamella is the front part of the eyelid. It includes the skin, the muscle under the skin (orbicularis muscle), and skin-related structures like eyelashes (cilia) and sweat glands (eccrine and apocrine glands)⁵
• The posterior lamella is the back part of the eyelid, which includes the conjunctiva (the thin lining on the inside of the eyelid), the meibomian glands (which produce oil for the tear film), and the tarsal plate (a firm piece of tissue that gives the eyelid its shape)⁵

On average, the upper eyelid has about 100–150 eyelashes, while the lower eyelid has 50–75.⁵

Signs and symptoms

People with trichiasis may experience a variety of symptoms, including:

• Changes in vision
• Sensitivity to light (photophobia)
• Eye pain or discomfort
• Redness in the eyes
• Tearing or watery eyes
• A sensation that something is stuck in the eye (often described as a "foreign body" feeling)

When a doctor examines the eye, they may observe:

• Eyelashes growing in the wrong direction, rubbing against the eye
• Entropion, where the upper and/or lower eyelids turn inward
• Redness and irritation of the conjunctiva (the thin membrane covering the white of the eye)
• Small scratches on the surface of the eye (called superficial punctate keratopathy or corneal abrasions)
• Inflammation of the cornea (keratitis)
• Thickening or roughening of the surface of the eye (keratinisation)

These signs can help eye care professionals diagnose the condition and determine its severity.⁵

Diagnosis

Trichiasis is usually diagnosed through a clinical eye examination. During the exam, the doctor carefully checks the edge of the eyelid, the inner surface of the eyelid (tarsal conjunctiva), the eye socket area (fornix), the white of the eye (bulbar conjunctiva), and the cornea to rule out any serious underlying conditions.⁴

In some cases, lash loss (madarosis) or eyelid thickening could be warning signs of eyelid cancers, such as sebaceous carcinoma, so these symptoms should be investigated thoroughly.⁴

Trichiasis may also be one of the early signs of mucous membrane pemphigoid (MMP)—a rare autoimmune disease that causes scarring of the eyes and other mucous membranes.⁴

In more advanced cases of trachoma, symptoms may include:

• Inward-turning eyelids (entropion)
• Scarring of the cornea
• Reduced vision
• Ongoing inflammation of the conjunctiva⁴

If trichiasis is seen along with signs of scarring on the conjunctiva, doctors may suspect MMP. In these cases, they often perform a conjunctival biopsy and use a test called direct immunofluorescence (DIF) to look for specific immune changes.⁴ However, it's important to note that a negative DIF test does not completely rule out MMP.⁴

If trachoma is suspected, especially in a patient with trichiasis, doctors may use nucleic acid amplification tests (NAATs) on a sample from the eye to confirm the diagnosis.⁴

When a patient shows signs of trichiasis and conjunctival scarring, but tests are negative for MMP, doctors will still consider other possible causes, such as:

• Chemical burns
• Trauma
• Stevens-Johnson syndrome
• Allergies (atopy)
• Medication-related toxicity⁴

Even if a clear diagnosis isn't immediately found, treatment such as immunomodulation therapy (which helps control the immune system) may still be recommended to prevent further eye damage.⁴

Management and treatment

Trichiasis is a condition where misdirected eyelashes rub against the eye, causing irritation and, over time, can lead to scarring of the cornea. There are several treatment options available, depending on the severity of the condition and the patient's preferences.³

• Tweezing or plucking the eyelashes can provide quick relief, but this is not a permanent solution, as the lashes usually grow back
• Electrolysis is a more lasting treatment. It involves using a small electric current to destroy the hair root at the base of the lash follicle, preventing regrowth³
• Cryoablation (also called cryosurgery) uses extremely cold gas to freeze and destroy the hair follicles. This is an effective way to permanently remove problem lashes. It can also be done along with eyelid splitting surgery, where the eyelid is gently opened to expose and remove the hair follicles more precisely³
• Laser ablation is another permanent method. Different types of lasers, including argon, ruby, infrared diode, and Nd: YAG lasers, can be used to target and destroy the lash follicles³
• A newer surgical option involves realigning the eyelash follicles rather than removing them. This technique allows the lashes to continue growing, but in the correct direction. This may be ideal for patients who want a more natural look. The best treatment approach often depends on the number of misdirected lashes and how natural the patient wants the result to appear³
  

In some cases, medications may contribute to the problem. For example, topical prostaglandin eye drops (used for conditions like glaucoma) can cause eyelash misdirection. If this might be the cause, the patient should talk to their ophthalmologist about changing their medication.

For patients with trachoma-related trichiasis, a single dose of the antibiotic Azithromycin after surgery has been shown to significantly reduce the risk of recurrence, especially when compared with using topical Tetracycline for six weeks.⁵

Summary

Trichiasis is a complex eye condition where eyelashes grow inward and rub against the eye, causing pain and potentially serious damage, including blindness if left untreated. Trauma-induced trichiasis, caused by injuries like chemical burns or surgery, presents particular challenges and requires careful management.

The condition can arise from various causes, including infections such as trachoma, a major cause of blindness worldwide, as well as congenital factors and inflammatory diseases that change the eyelid’s structure. The constant rubbing of misdirected lashes on the eye’s surface can lead to ulcers, scarring, and vision loss. Recognising symptoms like eye pain, redness, tearing, and the feeling of something in the eye is vital for early diagnosis and treatment.

Doctors diagnose trichiasis primarily through a thorough eye exam, sometimes using advanced tests when infections or autoimmune diseases are suspected. It is important to distinguish trichiasis from similar conditions to ensure the right treatment.

Treatment depends on the severity and cause. Temporary fixes like plucking lashes provide short-term relief, while more permanent solutions include electrolysis, cryoablation, laser therapy, and surgery to correct eyelash growth. For patients with trachoma-related trichiasis, postoperative antibiotic therapy helps prevent the condition from returning.

Beyond physical symptoms, trichiasis significantly impacts quality of life due to ongoing discomfort and vision problems. Early diagnosis and effective treatment are essential to protect eyesight and reduce suffering. Improving awareness and access to treatment, especially in areas where trachoma is common, can greatly reduce the burden of this condition. Advances in medical and surgical care continue to improve outcomes, offering hope for better eye health and well-being for those affected.