Ocular Manifestations Of Frontofacionasal Dysplasia: Eye-Related Complications And Abnormalities In Frontofacionasal Dysplasia

Introduction

Frontofacionasal Dysplasia is a rare autosomal recessive genetic condition. Individuals with Frontofacionasal Dysplasia usually present with facial and skull irregularities.¹ These include a short, wide head, abnormally shaped eyelids, and a cleft lip. This article will provide a comprehensive overview of ocular manifestations associated with Frontofacionasal Dysplasia, along with their diagnosis methodology and management strategies.

Ocular Manifestations and Eye Complications in Frontofacionasal Dysplasia

The following section will detail abnormalities found with structural eye development and the anterior (front) segment of the eye.

Structural ocular manifestations 

1. Microphthalmia

 In Frontofacionasal Dysplasia, Microphthalmia is defined as an abnormality where one or both eyes are unusually small or underdeveloped.^2,5 This can lead to significant visual impairment or even blindness, depending on the severity.²

2. Hypertelorism 

Hypertelorism is when there is an abnormally large distance between the eyes. In Frontofacionasal Dysplasia, hypertelorism is a common feature and can affect the overall facial appearance.⁵  

Anterior segment 

1. Absent inner eyelashes 

In Frontofacionasal Dysplasia, some individuals may be born without inner eyelashes on their upper eyelids.⁵ This feature can affect the natural appearance and reduce the eyelid's ability to protect the eye from dust and debris.

2. Aplasia or Hypoplasia of the eyebrow

Aplasia is the absence of the eyebrow, whereas Hypoplasia is where you have sparse remnants of the eyebrow.⁹

3. Blepharophimosis

In Frontofacionasal Dysplasia, Blepharophimosis is the condition where the eye openings are narrow or small.⁵ The eyelids can present as droopy, with folds of the skin on the inner corners of an individual’s eyes. This feature can contribute to vision problems by limiting the amount of light entering the eye.¹⁰ 

4. Telecanthus 

Telecanthus is when the inner corners of your eyelids are spaced farther apart than usual. This wider space is due to the abnormal development of the facial bones and tissues, which impacts the overall appearance of the eyes and face.¹⁶ 

5. Ptosis

In Frontofacionasal Dysplasia, Ptosis is a condition where the upper eyelid droops down over the eye.⁵ This drooping occurs because the muscles that lift the eyelid are underdeveloped or weak. Ptosis can vary in severity, sometimes slightly affecting the eyelid, or in more severe cases, nearly covering the entire eye. This can lead to vision problems and may require treatment to prevent long-term vision impairment.¹¹

6. Coloboma

In individuals with Frontofacionasal Dysplasia, coloboma is a condition present at birth where some tissue in or around the eye is missing.⁵ This gap, called the choroidal fissure, occurs as the eye is developing.¹² Coloboma can affect one or both eyes, and it can occur in different parts of the eye, leading to various types of conditions.¹²

1. Upper eyelid coloboma

An upper eyelid coloboma is a condition where a part of the upper eyelid is missing at birth. This gap or notch in the eyelid can affect how well the eyelid functions and may impact the protection of the eye.⁶

2. Iris coloboma

Iris coloboma is a condition where part of the iris (the colored part of the eye) is missing. In Frontofacionasal Dysplasia, this gap in the iris can occur as part of the broader spectrum of facial and eye abnormalities associated with the condition.⁵ The coloboma usually looks like a keyhole or notch at the edge of the pupil, and it can affect vision depending on its size and location.⁷ In some cases, it may cause light sensitivity or blurred vision.¹²

7. Microcornea

In Frontofacionasal Dysplasia, microcornea is a condition where the cornea (the clear, curved surface that covers the front of the eye), is abnormally small.⁵ The cornea focuses light into the eye to enable clear vision. Individuals with Frontofacionasal Dysplasia who have microcornea may experience vision problems because the small cornea doesn't bend light correctly, potentially leading to blurry or impaired vision.¹³

8. Cataract

The lens is located behind the colored part of the eye and is transparent and flexible to help focus light on the retina to enable clear vision. In Frontofacionasal Dysplasia, a cataract can be one of the eye-related complications.⁵ A cataract is when the lens becomes cloudy, which can block or scatter the light entering the eye and lead to blurry vision.⁸ 

Ocular Diagnostic Approaches in Frontofacionasal Dysplasia

The following sections will give an overview of how ocular manifestations associated with Frontofacionasal Dysplasia can be investigated.

Prenatal investigations

A prenatal ultrasound can be used by clinicians to monitor a baby's health before birth. It can also detect abnormalities such as Microphthalmia as early as 18 weeks into pregnancy.⁴

Imaging scans 

Most patients with Frontofacionasal Dysplasia are diagnosed at birth through a detailed physical examination and specific tests like CT imaging scans.⁵

Examining the front part of the eye  

A member of the ophthalmology team can use a slit-lamp, which acts as a microscope with a light to examine the front part of the eye, which includes; eyelids, cornea, iris, and lens. 

Assessing vision and refractive errors

Visual acuity can be assessed by asking an individual to look at an eye chart at different distances.³ This is conducted with both eyes open and each eye individually. This will determine the level of vision. A refractive error examination can reveal whether an individual needs glasses or contact lenses, which is crucial for visual development, especially in children. If vision in one or both eyes is affected, it may lead to amblyopia (reduced vision).    

Treatment and Management Strategies of Ocular Conditions in Frontofacionasal Dysplasia

While there is no cure for Frontofacionasal Dysplasia, treatment aims to manage the various associated ocular conditions. The following section will detail ocular treatment options. 

Glasses or lenses 

Glasses or lenses to correct refractive error can help to improve vision in conditions such as cataracts and microcornea.¹⁷ Additionally, specialised contact lenses or glasses can help shield the eye from light sensitivity and improve visual comfort for conditions such as iris coloboma. 

Surgery

1. Blepharophimosis surgery 

Blepharophimosis surgery aims to improve eyelid function, enhance appearance.¹⁵

2. Ptosis surgery 

The specific approach depends on the severity of the ptosis and the underlying cause. The goal of ptosis surgery is to restore normal eyelid function and enhance the patient’s overall quality of life.¹⁴

3. Coloboma surgery 

Eyelid coloboma surgery aims to repair the missing eyelid tissue and restore its normal appearance and function. During the procedure, a surgeon typically uses skin grafts or flaps to fill in the gap and reconstruct the eyelid.⁶ The specific techniques used depend on the size and location of the coloboma.

Visual aids 

Devices like magnifying glasses, specialised lenses, and electronic aids can help individuals utilise their vision better.

Summary 

Ocular abnormalities associated with Frontofacionasal Dysplasia include cataracts, ptosis, and coloboma. Healthcare usually prioritises increasing the visual potential of an individual, the protection of an individual’s eyes, and increasing comfort. Early detection and specialised care are key for managing ocular abnormalities associated with Frontofacionasal Dysplasia.