Megalocornea

Megalocornea is a rare, non-progressive eye disorder characterized by an abnormally large cornea. The cornea is the clear, dome-shaped surface that covers the front of the eye. In individuals with megalocornea, the diameter of the cornea is typically more than 13 millimeters, compared to the average diameter of 11.5 to 12 millimeters.

Causes

Megalocornea is usually an inherited condition, passed down in families through an X-linked recessive pattern of inheritance. This means that the condition is caused by a mutation in a gene on the X chromosome. The most common gene associated with megalocornea is the CHRDL1 gene.

Symptoms

The primary symptom of megalocornea is an abnormally large cornea. Other symptoms can include nystagmus (involuntary eye movement), astigmatism (blurred vision due to an irregularly shaped cornea), and myopia (nearsightedness). However, vision is typically not significantly affected in individuals with megalocornea.

Diagnosis

Megalocornea is typically diagnosed through a comprehensive eye examination. This can include a slit lamp examination, which allows the doctor to examine the structures at the front of the eye under magnification. Other diagnostic tests can include corneal topography, which maps the surface of the cornea, and optical coherence tomography (OCT), which provides cross-sectional images of the eye.

Treatment

There is no cure for megalocornea, and treatment is typically focused on managing any associated symptoms. This can include prescription glasses or contact lenses to correct astigmatism or myopia. In some cases, surgery may be required to correct associated conditions such as glaucoma or cataracts.

See also

• Cornea
• Eye disorder
• X-linked recessive inheritance
• CHRDL1