Cornea plana 2

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Cornea plana 2
Synonyms	Flat cornea 2
Pronounce	N/A
Specialty	N/A
Symptoms	Reduced visual acuity, hyperopia, astigmatism, glaucoma
Complications	Keratoconus, cataracts
Onset	Congenital
Duration	Lifelong
Types	N/A
Causes	Mutations in the KERA gene
Risks	Family history of the condition
Diagnosis	Genetic testing, slit-lamp examination
Differential diagnosis	Corneal dystrophy, keratoconus
Prevention	None
Treatment	Corrective lenses, surgery
Medication	N/A
Prognosis	Variable, depending on severity
Frequency	Rare
Deaths	N/A

Cornea Plana

Diagram of autosomal recessive inheritance pattern.

Cornea plana is a rare congenital disorder characterized by a flattened corneal curvature. This condition can lead to significant refractive errors and visual impairment. Cornea plana can be classified into two types based on its genetic inheritance pattern: autosomal dominant and autosomal recessive.

Pathophysiology

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. In cornea plana, the normal convex curvature of the cornea is reduced, resulting in a flatter surface. This alteration in shape affects the eye's refractive power, often leading to hyperopia (farsightedness) and other visual disturbances.

Genetics

Cornea plana can be inherited in an autosomal recessive or autosomal dominant manner. The autosomal recessive form is more severe and is associated with mutations in the KERA gene, which encodes keratocan, a protein essential for maintaining corneal structure and transparency.

Autosomal Recessive Cornea Plana

In the autosomal recessive form, both parents must carry one copy of the mutated gene, and the affected individual inherits two copies of the mutation. This form is often associated with additional ocular abnormalities, such as sclerocornea and microphthalmia.

Clinical Features

Patients with cornea plana typically present with:

• Reduced visual acuity
• Hyperopia
• Astigmatism
• Increased risk of glaucoma

In severe cases, patients may also exhibit nystagmus and strabismus.

Diagnosis

Diagnosis of cornea plana is primarily clinical, based on the characteristic flattening of the cornea observed during an eye examination. Keratometry and corneal topography are used to measure the corneal curvature and confirm the diagnosis. Genetic testing can identify mutations in the KERA gene, particularly in the autosomal recessive form.

Management

Management of cornea plana focuses on correcting refractive errors and monitoring for complications. Options include:

• Prescription of corrective lenses (glasses or contact lenses)
• Regular monitoring for glaucoma
• Surgical interventions, such as corneal transplantation, may be considered in severe cases.

See also

• Cornea
• Refractive error
• Genetic disorders