Coloboma
A coloboma is collective term encompassing any focal discontinuity in the structure of eye, and should not be confused with staphylomas which are due to choroidal thinning. Most commonly colobomas are due to failure of closure of the choroidal fissure posteriorly. Typically colobomas are bilateral, small and usually not associated with other deeper abnormalities.
Variants
- Morning glory syndrome - optic nerve head coloboma with associated midline structural abnormalities of the brain and skull.
- Coloboma with cyst (aka microphthalmia with cyst) - results from proliferation of the embryonic retina with potential extrusion of the vitreous posteriorly into the cyst (thus microphthalmia). The cyst may be come discontinuous from the eye, be larger than the eye, and may cause proptosis.
