Rare eye condition
Coloboma in adults
A coloboma is a gap in the iris, retina, choroid or optic nerve left when the eye's fetal fissure fails to close; adults living with coloboma need awareness of retinal detachment risk and tailored monitoring.
Key points
The essentials at a glance.
What to look out for, how the diagnosis is confirmed, who looks after it, and the options that exist.
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01
Vision impact ranges from none (small iris coloboma) to severe (large optic disc or macular involvement).
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02
Retinal detachment risk is increased when the retina and choroid are involved - new flashes, floaters or shadows need same-day review.
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03
Colobomas can be isolated or part of syndromes such as CHARGE; genetics review is worthwhile where other features exist.
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04
Photophobia from iris coloboma responds to tinted or cosmetic contact lenses.
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Regular dilated retinal examination is sensible surveillance for chorioretinal coloboma.
Understanding it
What it is, and what happens next.
In plain English - what is going on, how specialists confirm it, and the routes to treatment in the UK.
During fetal development the eye folds shut along a seam underneath; a coloboma is the notch left where the seam did not complete. In adulthood the condition itself is stable, but eyes with chorioretinal colobomas carry fragile margins where the thin membrane covering the gap meets normal retina - the site where detachments arise.
Adults with coloboma benefit from a baseline specialist assessment mapping exactly which structures are involved, an honest discussion of detachment warning signs, and periodic dilated review; those with iris involvement gain simple comfort from tints, and anyone with associated hearing, heart or growth features merits a genetics referral. In many parts of the UK, routine NHS outpatient referrals for problems like this can take several months, whereas an initial appointment with a private consultant is typically available within around two weeks.
A quiet reminder
This guide is for information, not medical advice.
Your GP or specialist knows your history and can tell you which parts apply to you. If in doubt, speak to them.
Published 2026-09-27 · Next review 2027-09-27
Frequently asked
Common questions about Coloboma in adults.
Quick, plain-English answers to what people ask us most.
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What is a coloboma?
A coloboma is a gap or missing piece of tissue in part of the eye, present from birth, resulting from incomplete closure of the developing eye structure during pregnancy. It can affect the iris (giving a distinctive keyhole-shaped pupil), the retina, the optic nerve, or other parts of the eye, and can affect one or both eyes. This covers how coloboma can affect vision and be managed in adulthood.
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What causes a coloboma?
It results from incomplete closure of a structure called the optic fissure during early eye development in the womb, and can occur in isolation or as part of a broader genetic syndrome affecting multiple body systems, such as CHARGE syndrome. In many isolated cases, no specific genetic cause is identified despite investigation. Genetic testing may be considered, particularly if there are other associated features suggesting a broader syndrome.
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How does a coloboma affect vision in adults?
The visual impact depends heavily on which part of the eye is affected and how extensive the gap is — an iris coloboma alone may cause only mild light sensitivity or cosmetic appearance changes, while a coloboma affecting the retina or optic nerve can cause more significant, sometimes substantial, vision loss in the corresponding part of the visual field. Vision impact, once established from birth, is generally stable throughout life rather than progressive, though associated complications can occasionally develop. An ophthalmologist can clarify the specific pattern and extent of visual impact for an individual's particular coloboma.
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Are there any risks or complications to be aware of in adulthood?
People with retinal coloboma have an increased risk of retinal detachment, since the edges of the coloboma can be a weaker point in the retina, so regular monitoring is often recommended even without new symptoms. Cataracts and glaucoma may also occur at a higher rate in some people with coloboma. Regular ophthalmology follow-up helps monitor for and manage these potential complications proactively.
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How is coloboma managed in adults?
Management focuses on maximising remaining vision through appropriate glasses or low-vision aids if needed, regular monitoring for complications such as retinal detachment, and, for iris coloboma affecting cosmetic appearance or causing significant light sensitivity, options such as tinted contact lenses. There is no treatment that restores the missing tissue itself, since this is a structural difference present from birth. Ongoing ophthalmology follow-up is generally recommended throughout life given the associated risks.
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When should I see a specialist?
If you have a known coloboma and haven't had regular ophthalmology follow-up, or notice any new visual symptoms such as flashes, floaters, or a shadow in your vision (which could suggest retinal detachment and needs urgent assessment), see an ophthalmologist. NHS ophthalmology referral can take several weeks for routine review; a private consultation is typically available within about 2 weeks, with urgent symptoms needing same-day emergency eye assessment.