macular corneal dystrophy

Macular Corneal Dystrophy (MCD) Description

Macular corneal dystrophy (MCD) is a rare and severe form of stromal corneal dystrophy characterized by bilateral ill-defined cloudy regions within a hazy stroma [12]. This condition leads to progressive opacification of the cornea, resulting in severe visual impairment [11].

Key Features:

• Bilateral involvement: MCD affects both eyes, with increasing corneal cloudiness throughout life.
• Progressive opacification: The cornea becomes increasingly cloudy, leading to vision loss.
• Variable onset: Corneal haze can be seen in infancy but usually becomes apparent in the second or later decades of life.
• Severe visual impairment: Visual impairment can be severe, especially by mid-life.

Genetic Basis:

MCD is an autosomal recessive condition caused by mutations in the carbohydrate sulfotransferase gene (CHST6), resulting in abnormal proteoglycan synthesis [10]. This leads to the accumulation of abnormal glycosaminogycans in the corneal epithelium and stroma, causing progressive opacification of the cornea.

References:

• [12] Macular corneal dystrophy (MCD) is a rare, severe form of stromal corneal dystrophy...
• [11] Macular corneal dystrophy is a progressive, bilateral disorder with increasing corneal cloudiness throughout life.
• [10] Macular Corneal Dystrophy is an autosomal recessive genetic disorder caused by mutations in the carbohydrate sulfotransferase gene (CHST6)...

Symptoms of Macular Corneal Dystrophy

Macular corneal dystrophy (MCD) is a rare genetic disorder that affects the cornea, leading to progressive vision loss. The symptoms of MCD can vary in severity and may not be noticeable in the early stages.

• Vision Loss: One of the primary symptoms of MCD is progressive vision loss, which can become severe over time [1].
• Clouding of the Cornea: The corneas become cloudy due to the accumulation of abnormal material, leading to a decrease in vision [2].
• Black Spots in Central Vision: Some individuals may experience black spots or blind spots in their central vision [3].
• Lines Appearing Bent or Wavy: The lines and shapes may appear distorted or bent, making it difficult to perform daily tasks [4].
• Increased Light Sensitivity: People with MCD may be more sensitive to light, which can cause discomfort [5].

Other Possible Symptoms

In some cases, individuals with MCD may experience additional symptoms, including:

• Corneal Edema: Swelling of the cornea
• Recurrent Corneal Erosions: The cornea may become irritated and inflamed, leading to recurring erosions
• Photophobia: Increased sensitivity to light

It's essential to note that these symptoms can be similar to those experienced by individuals with other eye conditions, such as cataracts or glaucoma. A comprehensive eye exam is necessary to rule out all possible eye health issues and confirm the diagnosis of MCD.

References: [1] - #8 [2] - #10 [3] - #7 [4] - #11 [5] - #15

Diagnostic Tests for Macular Corneal Dystrophy

Macular corneal dystrophy (MCD) is a rare inherited corneal disorder that affects vision. Diagnosing MCD can be challenging, but several tests can help confirm the condition.

• Genetic testing: Genetic testing of the CHST6 gene can reliably determine whether an individual is a genetic carrier of macular corneal dystrophy [1].
• Corneal biopsy: A corneal biopsy may reveal deposits of glycosaminoglycans, which stain with certain dyes, indicating MCD [4].
• Targeted gene panels: Targeted gene panels for anterior segment dysgenesis can also be used to diagnose MCD [5].
• Whole exome sequencing: Whole exome sequencing and whole genome sequencing may also be used to confirm the diagnosis of MCD [5].

Additional Tests

While not specific to MCD, other tests may be performed as part of a comprehensive eye exam to rule out other conditions or assess the severity of MCD. These include:

• Autofluorescence: Autofluorescence photos can study the retina and measure the progression of geographic atrophy in patients with advanced, dry AMD [15].
• Eye care professionals may use various tests, such as retinal photography, angiography, and optical coherence tomography, to diagnose macular degeneration, which shares some similarities with MCD [11][12].

It's essential to consult an eye doctor (ophthalmologist or optometrist) for a comprehensive eye exam and accurate diagnosis of MCD.

References:

[1] - Genetic testing of the CHST6 gene will reliably determine whether a dog is a genetic Carrier of macular corneal dystrophy. [6]

[4] - Corneal biopsy, which is not clinically indicated in patients with macular corneal dystrophy (MCD), reveals deposits of glycosaminoglycans, which stain with certain dyes. [4]

[5] - Targeted gene panels (anterior segment dysgenesis) · Whole exome sequencing · Whole genome sequencing. [5]

[11] - Ophthalmologists and optometrists diagnose macular degeneration as part of a comprehensive eye exam. Accurate diagnosis is made through a combination of a clinical exam and specific tests. These can include retinal photography, angiography, and optical coherence tomography. [11]

[12] - Macular degeneration is an age-related eye disease that affects central vision. Learn about the types, stages, diagnosis and treatment options for this condition that can cause blurred, wavy or blank spots in your vision. [12]

[15] - Eye care professionals use autofluorescence photos to study the retina and measure the progression of geographic atrophy in patients with advanced, dry AMD. [15]

Treatment Options for Macular Corneal Dystrophy

Macular corneal dystrophy (MCD) is a rare and inherited condition that affects the cornea, leading to vision loss. While there is no cure for MCD, various treatment options are available to manage its symptoms and slow down disease progression.

Medications

Several medications have been explored as potential treatments for MCD:

• Hypertonic saline: This medication has been shown to increase adherence of the epithelium to the cornea, reducing the risk of recurrent corneal erosions [5].
• Enzyme replacement therapy: Animal studies suggest that enzyme replacement therapy may be effective in treating MCD by clearing accumulated keratan sulfate [9].

Other Therapies

In addition to medications, other therapies have been investigated for their potential benefits:

• Corneal transplant (keratoplasty): This surgical procedure involves replacing the damaged cornea with a healthy donor cornea. While it can improve vision, it is not a cure for MCD [11].
• Laser therapy: Laser treatment may be an option for managing recurrent corneal erosions and improving vision [12].

Emerging Treatments

Research is ongoing to develop more effective treatments for MCD:

• Fresh Corneal Lenticule Implantation: This surgical procedure has been investigated as a potential treatment for MCD, with promising results [8].
• Regenerative therapies: New research is focused on regenerating the corneal endothelial layer, which may lead to more effective treatments for MCD [15].

Symptomatic Management

While these treatments aim to address the underlying causes of MCD, symptomatic management remains essential:

• Artificial tears and lubricants: These can help alleviate symptoms such as dryness and discomfort.
• NSAIDs: Nonsteroidal anti-inflammatory drugs may be prescribed to manage pain and inflammation.

It is essential to consult with a qualified eye care professional for personalized advice on managing MCD.

Differential Diagnosis of Macular Corneal Dystrophy

Macular corneal dystrophy (MCD) is a rare and inherited eye disorder characterized by progressive vision loss due to accumulation of abnormal glycosaminoglycans in the cornea. When diagnosing MCD, it's essential to consider other conditions that may present with similar symptoms. Here are some differential diagnoses for macular corneal dystrophy:

• Mucopolysaccharidoses (MPS): MPS is a group of genetic disorders caused by the deficiency of enzymes needed to break down and recycle sugar molecules. MCD can be confused with MPS due to similarities in clinical presentation, including corneal opacities and vision loss [3][4].
• Schnyder Corneal Dystrophy: Schnyder dystrophy is a rare, autosomal dominant disorder characterized by corneal lipid deposits. While it presents differently than MCD, it can be considered in the differential diagnosis due to similarities in corneal opacities [2][5].
• Lattice Corneal Dystrophy: Lattice dystrophy is another type of corneal dystrophy that can present with similar symptoms to MCD. It's essential to consider this condition when evaluating patients with progressive vision loss and corneal opacities [6][13].
• Fuchs Corneal Dystrophy: Fuchs dystrophy is a common, autosomal dominant disorder characterized by corneal edema and vision loss. While it presents differently than MCD, it can be considered in the differential diagnosis due to similarities in corneal opacities [9][10].
• Congenital Stromal Corneal Dystrophy: This rare condition is characterized by corneal opacities and vision loss present at birth. It can be confused with MCD due to similar clinical presentation [15].

It's essential to note that a comprehensive evaluation, including clinical examination, imaging studies (e.g., OCT), and genetic testing, is necessary to accurately diagnose macular corneal dystrophy and rule out other differential diagnoses.

References:

[1] Groenouw W. Über eine eigent