Excerpt from Megalocornea

Synonyms, Key Words, and Related Terms: enlarged cornea, corneal enlargement, anterior megalophthalmos, cataracts, glaucoma

Please click here to view the full topic text: Megalocornea

Background

Megalocornea is a nonprogressive enlargement of the cornea to 13 mm or greater. The cornea and the limbus are enlarged, but the cornea itself is histologically normal. Megalocornea is usually seen as an isolated finding, but it may be associated with other ocular and systemic findings. The additional ocular findings are found in anterior megalophthalmos, which includes an enlarged ciliary ring and crystalline lens in addition to an enlarged cornea.

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, spontaneous arrest of congenital glaucoma, and exaggerated growth of the cornea. Abnormal collagen synthesis may play a role.

Frequency

United States

No data are available.

International

No data are available.

Mortality/Morbidity

Morbidity and mortality can be secondary to the many systemic conditions found in association with megalocornea. See Special Concerns.
Ocular morbidity is associated with anterior megalophthalmos. An enlarged ciliary ring causes zonular stretching, leading to phacodonesis, ectopia lentis, iridodonesis, iris stromal hypoplasia and transillumination defects, Krukenberg spindles, and trabecular meshwork pigmentation. Other findings are posterior embryotoxon, Rieger anomaly, goniodysgenesis, and cataracts. Goniodysgenesis and pigment dispersion can contribute to glaucoma.

Sex

Males account for 90% of cases because X-linked recessive inheritance is most common.

Age

Megalocornea is present from birth.

Please click here to view the full topic text: Megalocornea

We subscribe to the
HONcode principles of the
Health On the Net Foundation

Medicine is a constantly changing science and not all therapies are clearly established. New research changes drug and treatment therapies daily. The authors, editors, and publisher of this journal have used their best efforts to provide information that is up-to-date and accurate and is generally accepted within medical standards at the time of publication. However, as medical science is constantly changing and human error is always possible, the authors, editors, and publisher or any other party involved with the publication of this article do not warrant the information in this article is accurate or complete, nor are they responsible for omissions or errors in the article or for the results of using this information. The reader should confirm the information in this article from other sources prior to use. In particular, all drug doses, indications, and contraindications should be confirmed in the package insert. FULL DISCLAIMER