TABLE 1-2. Summary of Syndromes of Ocular Malformations.
Anterior segment Ocular
Syndrome Microphthalmia dysgenesis coloboma Glaucoma
Optic disc coloboma
Leber's congenital amaurosis
Rieger's anterior segment dysgenesis
Upper lid coloboma
Source: NIH Online Mendelian Inheritance in Man: www3.ncbi.nlm.nih.gov/
macula, and optic nerve (Figs. 1-21, 1-22, 1-23). Colobomas are often associated with microphthalmia (colobomatous microphthalmia) or, less frequently, orbital or eyelid cysts (Fig. 1-22). Because the optic fissure closes first at the equator of the eye, and then in a posterior and anterior direction, colobomas are most frequently found at the two ends of the optic fissure, that is, iris and optic nerve. When the optic nerve is involved in the coloboma, vision is usually affected, in some cases causing blindness. Optic nerve colobomas may be associated with basal encephaloceles, which also represent a failure of fissure closure.59,85 Large choroidal colobomas may be associated with posterior pole staphylomas, causing macular disruption and poor vision. Occasionally, a line of choroidal colobomas occur along the fetal fissure area with skip areas (Fig. 1-23). Isolated iris colobomas usually do not affect visual acuity unless there is an associated refractive error. Typical iris colobomas occur infer-
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