By Admin, March 1, 2013

What is a coloboma?

A coloboma is a congenital defect in the structure of either the eyelid or the eye.

Is coloboma hereditary?

Coloboma can be inherited or can occur spontaneously.

What types of colobomas occur in the eye?

Coloboma may involve the iris, lens, retina, or optic nerve. The embryonic fissure normally closes around the 5th week of gestation (during pregnancy). Improper closure of the fissure causes a defect (coloboma) in one or more of the eye structures.

What is a coloboma of the eyelid?

It is a defect which varies from a small notch to near total absence of the eyelid. It most commonly affects the upper eyelid.

What other abnormalities occur with a coloboma of the eyelid?

Eyelid coloboma can be associated with Goldenhar syndrome, which is characterized by a growth on the eye (limbal dermoid), abnormal eye movement (Duane syndrome), ear abnormalities, or vertebral abnormalities.

How is a coloboma of the eyelid treated?

The eye usually requires extra lubrication to prevent drying of the surface, and eventually may require surgery to close the defect.

What is an iris coloboma?

Iris coloboma is a defect in the lower aspect of the colored part of the eye. The pupil is round above and elongated below making an old-fashoined “keyhole” shape [See figure 2]. All children with iris coloboma should have a complete eye exam by an ophthalmologist to look for structural defects inside the eye.

Does iris coloboma affect vision?

If no other abnormalities are present, vision may be normal. Some increase in light sensitivity may occur because of a larger pupil. Contact lenses that change eye color can be used to cover the iris coloboma.

What is a chorioretinal coloboma?

A small or large developmental defect may occur in the deeper structures of the eye or eyes. The defect can involve the retina (layer of nerves responsible for sight) and/or the optic nerve (connects the eye to the brain). Coloboma of the central retina or optic nerve can reduce vision, sometimes severely. The eye is occasionally smaller than normal.

Does a coloboma inside the eye affect vision?

If the coloboma involves the optic nerve or large areas of the retina, vision may be reduced. Depending on the extent of involvement, this varies from mild to severe reduction in vision.