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What Is a Complete Uveal Coloboma?

A complete uveal coloboma is a congenital defect in which the coloboma involves multiple uveal structures, often extending from the iris and ciliary body to the choroid and retina. It happens when the embryonic fissure does not close fully during early eye development. The appearance can include a keyhole-shaped pupil and a chorioretinal defect, typically in the inferior or inferonasal region. Vision impact varies widely and depends on whether the macula or optic nerve is involved.

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What Is a Complete Uveal Coloboma?

A complete uveal coloboma is a congenital defect in which the coloboma involves multiple uveal structures, often extending from the iris and ciliary body to the choroid and retina. It happens when the embryonic fissure does not close fully during early eye development. The appearance can include a keyhole-shaped pupil and a chorioretinal defect, typically in the inferior or inferonasal region. Vision impact varies widely and depends on whether the macula or optic nerve is involved.

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How it forms

During fetal development, the eye forms around a temporary gap called the embryonic fissure. If that fissure fails to close completely, a coloboma remains in the affected tissues. A complete uveal coloboma describes broader involvement across the uveal tract rather than a small, isolated defect. Some cases are sporadic, while others are linked to genetic syndromes or chromosomal conditions.

Signs and vision effects

Iris involvement may be obvious as a pupil defect and can cause glare or light sensitivity. Posterior involvement can reduce visual acuity, contrast, or visual field, especially if the defect is near the macula. Refractive error is common, and children may be at risk for amblyopia. An eye exam and imaging help determine which structures are affected.

Possible complications

Complication risk depends on location and extent of the coloboma. Posterior colobomas can increase the risk of retinal detachment because the tissue architecture is abnormal near the defect. Some patients may also develop choroidal neovascularization or cataract over time. Prompt evaluation of new flashes, floaters, or a curtain-like shadow is important.

Management and follow-up

Management focuses on optimizing vision and monitoring for complications. Glasses or contact lenses correct refractive error, and amblyopia therapy may be used in children when needed. Tinted lenses or other glare-reducing strategies can help with iris coloboma symptoms. Regular dilated retinal exams and symptom education are key parts of long-term care, and some patients may benefit from genetic counseling based on the clinical context.

FAQs on complete uveal coloboma

Is a complete uveal coloboma present at birth?

Yes. It forms during fetal development and is present at birth, even if it is not noticed right away. Severity determines when it is detected.

Does it always cause poor vision?

No. Some people have good vision, especially when the macula and optic nerve are not involved. Others have reduced vision from posterior involvement, amblyopia, or associated eye conditions.

Is retinal detachment a risk?

Yes, particularly when the coloboma involves the choroid and retina. The risk varies by anatomy, so regular monitoring is important. Seek urgent care for flashes, many new floaters, or a curtain-like shadow.

Can it be inherited?

It can be sporadic or associated with genetic or chromosomal conditions. If there is a family history or other health findings, genetic counseling may be recommended. Your clinician will guide which evaluation is appropriate.

References

Optic Nerve Coloboma. Vegunta S; Patel BC (StatPearls, NCBI Bookshelf). https://www.ncbi.nlm.nih.gov/books/NBK532877/. Date Accessed: February 18, 2026.

Ocular Coloboma: A Comprehensive Review for the Clinician. Lingam G, et al. https://www.nature.com/articles/s41433-021-01501-5. Date Accessed: February 18, 2026.

Coloboma of the Iris. MedlinePlus Medical Encyclopedia. https://medlineplus.gov/ency/article/003318.htm. Date Accessed: February 18, 2026.

Case Report: Association of Ocular Colobomas With a Novel CDC42 Variant. Brightman D, et al. https://pmc.ncbi.nlm.nih.gov/articles/PMC12353887/. Date Accessed: February 18, 2026.

Management of Anophthalmia, Microphthalmia and Coloboma Through Collaborative Neonatology and Ophthalmology Care. Russo M, et al. https://pmc.ncbi.nlm.nih.gov/articles/PMC11881466/. Date Accessed: February 18, 2026.