What is Eyelid Coloboma?

“Columba” comes from the Greek word “koloboma,” which means “cut short” or mutilated. This refers to a hole or gap in the eye tissue that is present when a baby is born. This irregularity usually comes about because the eye didn’t fully develop while the baby was in the womb. An eyelid coloboma means that there is a complete full-thickness gap in the edge of the eyelid. It might affect the eyelid, the colored part of your eye (iris), the lens (the part that helps you focus), the ciliary body (the part that produces fluid), the choroid (tissue that provides oxygen and nourishment), the retina (the part that reacts to light), or your optic nerve (the part that sends visual information from the eye to the brain).

Congenital eyelid coloboma can happen in one or both eyes, and can affect 1 to all 4 eyelids. The gap can be as small as a minor notch or as large as a complete full-thickness hole, affecting around a third to a half of the eyelid. Usually, it affects the upper eyelid more often, and it most commonly happens at the junction between the inner third and the middle third of the upper eyelid. Eyelid coloboma is a less severe version of cryptophthalmos, a condition that a baby can be born with that results in eyelid abnormalities because of a failure in differentiation (the process where cells become specialized).

What Causes Eyelid Coloboma?

An eyelid coloboma, which is an issue causing a gap in the eyelid, is believed to be a type of facial cleft, although the exact cause isn’t fully understood. It’s been suggested that it could be due to several factors experienced while a baby is in the womb, such as an amniotic band (strands of the amniotic sac that can entangle parts of the fetus), inflammation, poor blood flow in the placenta, physical factors, and unusual blood vessel systems. However, none of these have been definitively proven as the cause.

Eyelid colobomas are considered part of a group of disorders involving facial clefts. This group covers a wide range – from minor notches in the eyelid to complete cryptophthalmos, a condition where skin or hair covers the eye. Eyelid colobomas can be ranked on a scale from 1 to 5, with 1 being a simple coloboma and 5 being the most severe form, including cryptophthalmos along with nose and lip abnormalities.

Eyelid colobomas might occur by themselves or in combination with various other conditions. Some of these include:

Fraser syndrome, a rare condition involving eye, ear, and urinary tract abnormalities, with ambiguous genitalia and throat narrowing.
Goldenhar syndrome, characterized by facial asymmetry, growths around the eye and ear, an abnormal eye called microphthalmia, eyelid coloboma and vertebra anomalies like scoliosis.
Treacher Collins syndrome, involving a downward slant of the eyes, cataracts, small eyes, abnormal tear ducts, and possibly conductive deafness due to malformed ear bones.
CHARGE syndrome, which involves colobomas, heart defects, atresia of choanae (a closure or blockage of the nasal airway), growth retardation, genital abnormalities, and ear abnormalities.
Frontonasal dysplasia, characterized by widely spaced eyes, divided nose, and a medical facial cleft.
Delleman-Oorthuys syndrome which involves developmental abnormalities in the brain, eye and facial tags, and lip abnormalities.
Nasopalpebral lipoma coloboma syndrome, characterized by upper eyelid and nasopalpebral lipoma (benign tumors), both eyelid coloboma, telecanthus (an excessive distance between the eyes), and underdeveloped upper jaw.
Manitoba oculotrichoanal syndrome, involving eyelid coloboma, small or absent eyes, hair growths extending from scalp to eyebrow, a divided nose, and abnormalities of the belly button and anal opening.

While the exact cause of an eyelid coloboma remains unknown, understanding the condition and its potential associations with other conditions can be helpful in managing it.

Risk Factors and Frequency for Eyelid Coloboma

A condition known as Eyelid coloboma occurs in about 1 in 10,000 births and affects both genders equally. It isn’t specific to any racial group, apart from a condition called Manitoba oculotrichoanal syndrome which is observed especially in the indigenous population of Northern Manitoba. Interestingly, eyelid coloboma manifests in both eyes in about 44.4% of cases.

A closely related disorder, known as Goldenhar syndrome, is also linked to eyelid coloboma. This syndrome occurs in approximately 1 in 5,600 births.

Signs and Symptoms of Eyelid Coloboma

In cases of eyelid coloboma, careful medical history is essential to confirm the diagnosis. Eyelid coloboma is a birth defect, which means the missing eyelid tissue would be apparent from the time of birth. It’s important to rule out any trauma-induced damage to the eyelid. This condition is uncommon and often accompanies other body and eye abnormalities. Therefore, it’s necessary to examine a patient’s list of symptoms and review their medical records thoroughly.

During a physical exam, doctors look for signs of various abnormalities such as dermoids (a type of benign tumor), lipodermoids (a variant of dermoid), keratoconus (a condition in which the cornea, the front part of the eye, bulges out), iris coloboma (a hole in the iris), and micro-ophthalmia (a condition in which the eye is abnormally small). Patients with eyelid coloboma may present with insufficient conjunctiva (the clear tissue covering the front of the eye), tarsal plate (the dense, firm tissue within the eyelid), orbicularis oculi muscle (a muscle around the eye), and skin.

The defective eyelid leaves the cornea (front layer of the eye) exposed, which can lead to exposure keratopathy (damage caused by the cornea drying out) and secondary bacterial infections. Therefore, it’s crucial to examine the cornea for signs of damage and ulcers.

Any patient with an eyelid coloboma should undergo a comprehensive eye examination. This involves:

Assessing visual acuity (clarity of vision)
A pupil exam
Checking intraocular pressure (pressure inside the eye)
A dilated fundus examination (exam of the back of the eye)
Assessing for ocular misalignment (eyes not moving together as they should)
Cycloplegic refraction (a test to assess the eye’s focusing power with pupils dilated).

Testing for Eyelid Coloboma

If you’re having eye issues, especially something suspicious like an eyelid coloboma (a hole, gap or defect in the structure of your eyelid), your eye doctor may recommend some additional tests. These could include a corneal topography, which maps the surface of your eye, visual field testing to assess your whole field of sight, external and fundus photos for direct visualization of your eye, and optical coherence tomography which is a bit like an ultrasound of the eye that can help create a detailed image of it.

Beyond eye examinations, your general doctor might also perform a full physical check-up. This is because an eyelid coloboma is often linked with conditions that affect the whole body, known as syndromic conditions. If your doctor suspects there could be internal abnormalities, they may ask for some additional imaging tests. These tests can include x-rays, CT scans (computed tomography, a detailed type of x-ray), MRI scans (magnetic resonance imaging, which uses magnetic fields to create detailed images of the body’s soft tissues), or ultrasound (high-frequency sound waves are used to visualize the structure of the internal organs).

Treatment Options for Eyelid Coloboma

The primary goal of treating lid coloboma, a congenital eye condition, is to protect the cornea (the transparent front part of the eye covering the iris and pupil) and manage amblyopia (also known as “lazy eye”). If necessary, artificial tears and ointment, moist bandages, and bedtime patching can be used to help keep the cornea safe. An interprofessional evaluation to check for systemic deformities (problems affecting the entire body) is also recommended.

We expect every patient with lid coloboma to have amblyopia, because astigmatism (a type of refractive defect causing blurry vision) is common with this condition. In cases of Goldenhar syndrome, a rare birth defect associated with abnormalities of the eye, ear, and spine, there’s an additional risk of astigmatism and blocked vision that can further contribute to amblyopia.

Deciding when and what type of surgery to do depends on the size of the defect, the exposure of the cornea, and the overall health of the infant. If the defect is small and there’s no corneal exposure or vision blockage, the surgery can be delayed until the child is around 3 or 4 years old. However, there may be reasons to avoid general anesthesia, like if the child has palate defects or other health conditions.

Different surgical techniques are preferred based on the size of the defect. For small defects, a number of techniques can be used, including directly sewing the tissues together, a semicircular flap technique, or creating a flap of tissues to repair the cut area. In moderate defects, techniques may include using a lid switch flap (a type of grafting process) or a Cutler-Beard reconstruction (a two-stage procedure where skin from one area is moved to another). For severe defects, getting both cosmetic and functional results can be challenging.

Similarly, for reconstructing the lower eyelid, small defects can be managed the same way as in the upper eyelid. Moderate defects involve using grafts (transferring tissue) and advancing the skin, whereas larger defects call for more extensive procedures like flap surgeries and grafts.

Direct closure is chosen for small defects as it allows for a tensionless and layered wound closure. If the defects are in the center and can’t be closed directly, a semicircular flap can be used. The Cutler-Beard procedure, a two-step procedure, is used to repair large defects in the upper eyelid, but it’s not suitable for patients with one working eye due to the long waiting period between the two steps. It also comes with potential risks like inward rolling of the eyelid (entropion) and loss of eyelashes.

In case of large lower eyelid defects, the Hughes procedure is adopted. This also involves a two-stage process with the first step involving moving a part of the upper eyelid to replace the lower one, and the second is rebuilding of the lower eyelid. These steps are carried out months apart.

Lastly, the Mustarde cheek rotation flap procedure is useful for large, especially vertical, defects of the lower lid. Here, a large skin muscle flap is rotated from the cheek to repair large lower eyelid defects.

If someone is missing eyelid tissue, the reason might be because of an injury. But if the person has been missing this tissue since birth, it’s probably due to a condition called an eyelid coloboma. A doctor should watch out for certain syndromes that could confirm the diagnosis of an eyelid coloboma. These syndromes include:

Fraser syndrome
Goldenhar syndrome
Treacher Collins syndrome (also known as mandibulofacial dysostosis)
CHARGE syndrome
Frontonasal dysplasia
Delleman-Oorthuys (oculocerebrocutaneous) syndrome
Nasopalpebral lipoma coloboma syndrome
Manitoba oculotrichoanal (MOTA) syndrome
Conditions called anophthalmia and micophthalmia

What to expect with Eyelid Coloboma

The outlook is generally good for small to moderate defects, in terms of fixing the defect and maintaining the function of the eyelid. However, achieving a good appearance may be more challenging for severe defects. Some surgeries could cause irregular shapes in the eye (astigmatism) and decreased eye coverage, resulting in a condition called amblyopia or “lazy eye” and reduced vision clarity.

In one study, all 21 patients who had surgery for eyelid colobomas (a gap in the eyelid) had acceptable cosmetic results, and their vision strength compared to their other eye was similar. This suggests a good outlook for patients with eyelid colobomas who have early surgery.

Possible Complications When Diagnosed with Eyelid Coloboma

Eyelid colobomas often cause complications, leading to reduced vision in the affected eye. This condition can result in exposure keratopathy, a defect where the eye’s surface can’t maintain lubrication without the eyelid coverage, leading to faster evaporation of tear film and dryness. It can lead to the breakdown of the cornea’s protective layer, making the eye vulnerable to infectious keratitis, a severe eye infection.

Additionally, eyelid abnormalities can result in changes to the eye’s curvature, causing astigmatism, a condition distorting vision. If not treated timely, it may further cause amblyopia, commonly known as ‘lazy eye.’

Amblyopia often goes hand in hand with strabismus, another eye condition leading to unaligned eyes, which is also frequently seen in cases of eyelid coloboma. Besides, the lack of eyelid tissue can result in cosmetic deformities that can affect a person’s appearance.

Possible Complications of Eyelid Coloboma:

Reduced vision in the affected eye
Exposure keratopathy, leading to dry eyes
Infectious keratitis, a severe eye infection
Astigmatism, a condition affecting the eye’s focus
Amblyopia or ‘lazy eye’
Strabismus, a condition causing unaligned eyes
Cosmetic deformities affecting appearance

Preventing Eyelid Coloboma

Parents should take comfort in knowing that the appearance of their child’s eye will be taken into consideration with treatment. However, it is also important to maintain reasonable expectations. The main treatment goal is to enhance the functionality of the eyelid and preserve the eye’s visual ability. Addressing other eye problems such as astigmatism (an imperfection in the eye’s curvature), amblyopia (also known as lazy eye) and strabismus (crossed or turned eyes), will also be a part of the ongoing treatment. Parents should be prepared for the need for follow-up appointments to ensure the best possible visual outcome for the child.

If the child has associated syndromes, such as Treacher Collins syndrome which is an inherited condition passed down from parents, genetic counseling is crucial. This will help in understanding the condition better and managing it effectively.