Coloboma: A Very Rare Birth Defect

What comes to mind when you hear the term ‘birth defect’? If we read it in a medical journal, probably not much. But if it’s said in relation to our child, then what comes to mind? Concern? Fear, perhaps?

There is a rare congenital birth defect called Coloboma. The term ‘Coloboma’ in the Greek means ‘unfinished.’ Essentially, Coloboma occurs when the eye stops growing before it is fully developed.

A person with Coloboma has an eye or both eyes that look like a notch or keyhole shape in the pupil. It actually isn’t the pupil at all, but a malformation of the iris.

Have any of you ever seen anyone with Coloboma? Some are affected in one eye and some in both. Usually if both eyes are affected, vision is blurred. But that’s not always the case.

It’s estimated that Coloboma occurs in 1 of every 10,000 people.

During the first three months of pregnancy, the eyes of the baby are developing quickly, starting as a small bud which then sprouts out so that all the intricate parts of the inside of the eye can be formed and nourished. To aid this nourishment a gap, known as the fetal cleft, opens on the underside of each bud.When the intricate development of the eye is completed, the gap closes but in some cases the gap either does not close or closes only partially and such gaps will remain throughout life. This gap is Coloboma.This does not mean that there is a hole in the eye, just that certain structures within the eye do not fully form.

Rebecca has Coloboma in both eyes. One eye has a ‘keyhole’ effect, and the other isn’t as pronounced. Rebecca is my youngest daughter. She was born 13 years ago, and she was born squinting. She had ten fingers, ten toes, looked normal, except for the perpetual squint. I didn’t think too much about it, just figured she had not adjusted to being out in the light. Newborn’s eyes don’t open all that wide anyway, what with their chubby cheeks, so I didn’t notice at first that her eyes were different. Once I did, her doctor told me I would need to contact an opthalmologist. That’s when I first heard of Coloboma, and that’s when I first learned that my little baby had a birth defect. As you can imagine, I was concerned. I wanted to know what this meant, and how it would effect her life. Coloboma can be an indication of other congenital birth defects, including problems with the heart and mental retardation. Fortunately, these were ruled out and Rebecca’s vision is normal. However, she is sensitive to light and wears sunglasses during the summer. When someone is affected, their pupils don’t dilate or contract. Therefore their eyes let in more light, causing the sensitivity in bright light. It can also be painful. Also, with Rebecca, she sees better in the dark. When she was three, she was looking out the front door, fascinated. I looked out and didn’t see anything. She insisted there was a dog outside. Sure, enough, when we turned on the light, there he was.

Rachel also has Coloboma. She isn’t as fortunate as Rebecca. Her left eye is affected to the point where she is blind in that eye. Also, she has had brachial clefts in her neck, and has problems with hearing, speech, and learning capacity. Rachel’s schedule consists of occupational therapy, physical therapy, and speech therapy. She is now in a pre-K program designed for special needs kids. This specific combination of flaws is identified by the acronym “CHARGE” which stands for

C – Coloboma
H – Heart defects
A – Atresia of the choanae (blockage of the nasal passages)
R – Retarded growth and development
G – Genital hypoplasia (undescended testes)
E – Ear anomalies.

Fortunately CHARGE is very rare.

Coloboma is sometimes hereditary and sometimes not. In Rebecca’s case, it isn’t, therefore it’s called ‘sporadic’. None of her relatives as far back as we know has had it. Sometimes Coloboma occurs in all the children of a family to some extent. Twins have been known to have Coloboma.

Also, some dogs have been known to have Coloboma.

There is no cure, obviously. However, contact lenses can be worn to make the eye appear ‘normal’. I’ve mentioned that to my daughter but she says she likes her ‘cat eyes’. As her mom, I can rest easy knowing she is comfortable with that and that she has no other congenital defects. However, for those who aren’t so fortunate, more research needs to be done. If not for them, for those who aren’t yet born, that they may not have to deal with this rare birth defect.

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