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Coloboma means that part of the tissue that makes up the eye is missing. It’s a condition that people are born with — and it can affect 1 eye or both eyes. Each type of coloboma affects the eye or eyelid differently.

Eyelid coloboma

Eyelid coloboma means that part of the upper or lower eyelid is missing.

Eyelid coloboma usually affects the upper eyelid. It typically looks like a notch or gap in the eyelid, but in severe cases, the visible part of that eyelid may be completely missing.

Our eyelids protect the cornea — the clear front layer of the eye. For people with eyelid coloboma, the cornea doesn’t have this protection. If it isn’t treated, eyelid coloboma can lead to dry eye and vision problems.

Lens coloboma

Lens coloboma means that a part of the lens is missing. The lens is the clear inner part of the eye that helps to focus light on the retina — a light-sensitive layer of tissue at the back of the eye.

People with lens coloboma have a higher risk of cataracts, which can make your vision blurry, hazy, or less colorful.

Macular coloboma

Macular coloboma means that part of the macula is missing. The macula is a part of the retina that’s responsible for the sharp, central vision that you need for activities like reading or driving.

People with macular coloboma may have blurry vision or large blind spots.

Optic nerve coloboma

Optic nerve coloboma means that the optic nerve — a nerve that connects the eye to your brain — is not completely formed.

People with optic nerve coloboma may have blurry vision or blind spots.

Uveal coloboma

Uveal coloboma can affect 2 different parts of the eye: the iris and the retina.

Iris coloboma

When uveal coloboma affects the iris, it’s called iris coloboma. The iris is the colored part of your eye that surrounds your pupil — the opening in the middle of your eye where light enters the eye.  

In iris coloboma, part of the iris is missing, making the pupil look like a keyhole or a cat’s eye. People with iris coloboma may be sensitive to light because their pupil lets too much light in. They may get headaches or need to squint or close their eyes when they’re in bright light.

Chorio-retinal coloboma

When uveal coloboma affects the retina, it’s called chorio-retinal coloboma.

Chorio-retinal coloboma usually doesn’t cause vision problems. In rare cases, however, the retina may pull away from its normal position at the back of the eye. This is called retinal detachment.

Last updated: December 21, 2021