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CONGENITAL ABNORMALITIES OF THE EYE-MEGALOCORNEA (Diagnostic Studies…
CONGENITAL ABNORMALITIES OF THE EYE-MEGALOCORNEA
Definition
Megalocornea is a rare nonprogressive enlargement of the cornea to 13 mm or greater; in the setting of normal intraocular pressure.
Pathophysiology
Megalocornea is a developmental anomaly of unknown etiology. Postulated mechanisms of development include a defect in formation of the optic cup in which the anterior tips of the cup fail to fuse, allowing more space for the developing cornea.
Signs and Symptoms
Symmetric
Dome-shaped cornea
Normal corneal thickness
Normal endothelial cell density, usually bilateral
Usually good visual acuity
With-the-rule astigmatism common
Corneal diameter usually 13.0-16.5 mm
Medical Management
Medical care for patients with megalocornea includes correction of refractive error and thorough evaluation for findings of anterior megalophthalmos. Also, routine examination for the development of cataracts and glaucoma is necessary.
Causes
Megalocornea is inherited as an X-linked recessive trait (90% of cases).
Diagnostic Studies
Gonioscopy
A-scan ultrasound biometry
Specular microscopy
Surgical Management
Surgical amelioration of glaucoma and cataract is performed when necessary.
Risk Factors
Family history of megalocornea
Health Education
Advise parents of the potential for ocular complications and associated systemic conditions. Emphasize the importance of a thorough developmental evaluation and regular medical and ophthalmic follow-up care.
