Numerous congenital malformations of the cornea (“the windshield of the eye”) have been reported, many associated with other ocular and systemic abnormalities. Isolated megalocornea is one of these in which the cornea is larger than normal and usually occurs only in males.
Megalocornea is a rare congenital malformation of the cornea which can cause blurred vision. The cornea is larger than normal and sometimes the cornea loses some of its transparency later in life. Cataracts may occur and the iris may be thinned. Usually vision can be corrected to normal or near normal with glasses. Megalocornea may occur as an isolated problem or in association with more extensive disease.
Isolated megalocornea is usually found only in males as the gene found in most families is located on the X chromosome. Affected males cannot pass this mutation to their sons and it is not known to cause disease in carrier daughters. However, males can have affected grandsons among their daughters’ children.
Simple inspection of the eye can reveal an enlarged cornea. Eye professionals can measure the diameter of the cornea to document enlargement. A complete medical eye examination is important for other signs such as mild opacification may occur along with cataracts. Megalocornea can occur by itself but it is also sometimes seen in other syndromes so that complete medical examinations are recommended.