Contributor: Gordon K. Klintworth
Microcornea is an ocular developmental anomaly in which the radius of curvature of a clear cornea is smaller than normal and the corneal diameter is <10-10.5 mm. Microcornea may be an isolated abnormality in an otherwise normal eye, but this is uncommon and most instances it occur in eyes with microphthalmos. Microcornea is often found with other anterior segment malformations or with nanophthalmos; hyperopia, cataract and glaucoma. Simple or uncomplicated microcornea may arise from an overgrowth of the anterior tips of the optic cup so that it is smaller than normal but histologically unremarkable. Microcornea may be inherited and occurs in families with other developmental anomalies due to a faulty migration of neural crest cells (sclerocornea, mesodermal dysgenesis, and cataract with microcornea). Sometimes microcornea follows congenital rubella. Most cases are sporadic, but others may be inherited as an autosomal recessive [microphthalmos - autosomal recessive] or autosomal dominant [microphthalmos - autosomal dominant] disorder. When microcornea is present in an otherwise normal sized eye the normal growth of the lens may result in angle closure glaucoma [glaucoma - angle closure]. An autosomal dominant form of microcornea is associated with cataract and anterior segment abnormalities. Microcornea may be a manifestation of a variety of systemic syndromes, including Nance-Horan syndrome, Meyer-Schwickerath-Weyers sydrome, and the micro syndrome.