Coloboma is collective term encompassing any focal discontinuity in the structure of the eye, and should not be confused with staphylomas, which are due to choroidal thinning. 

Pathology

Most commonly colobomas are due to failure of closure of the choroidal fissure posteriorly. Typically colobomas are bilateral, small and are not accompanied by other deeper abnormalities. It occurs along the inferomedial aspect of the globe and optic nerve 2.

Associations
Variants
  • morning glory syndrome: optic nerve head coloboma with associated midline structural abnormalities of the brain and skull
  • coloboma with a cyst (microphthalmia with cyst): results from the proliferation of the embryonic retina with potential extrusion of the vitreous posteriorly into the cyst (thus microphthalmia). The cyst may become discontinuous from the eye, be larger than the eye, and may cause proptosis
Radiographic features

On CT or MRI, the affected globe is usually small 2 with a focal posterior defect in the globe with vitreous herniation 3. A retrobulbar fluid-density cyst may be present 3

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Article Information

rID: 5938
Tags: eye, cases
Synonyms or Alternate Spellings:
  • Ocular coloboma

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Cases and Figures

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    Coloboma: T2
    Case 1: on right with morning glory syndrome
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    Case 2
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