The additional ocular findings are found in anterior megalophthalmos, which includes an enlarged ciliary ring and crystalline lens in addition to an enlarged cornea. 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. 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. Megalocornea is present from birth. Family history of megalocornea may be present.