A patient with typical peripheral retinal coloboma.Kelly Aileen Oldstein, Certified Ophthalmic Photographer at Chester, County Eye Care and Owner, Kelly Aileen, Photography, West Chester, PA, USA.

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André Silva

Diseases & Syndromes

Head

Anatomy

Ophthalmology

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Coloboma

ColobomaColoboma is an eye abnormality that occurs before birth. Colobomas are missing pieces of tissue in structures that form the eye. They may appear as notches or gaps in one of several parts of the eye, including the colored part of the eye called the iris; the retina which is the specialized light-sensitive tissue that lines the back of the eye; the blood vessel layer under the retina called the choroid; or the optic nerves, which carry information from the eyes to the brain.Colobomas may be present in one or both eyes and, depending on their size and location, can affect a person's vision. Colobomas affecting the iris, which result in a "keyhole" appearance of the pupil, generally do not lead to vision loss. Colobomas involving the retina result in vision loss in specific parts of the visual field, generally the upper part. Large retinal colobomas or those affecting the optic nerve can cause low vision, which means vision loss that cannot be completely corrected with glasses or contact lenses.Some people with coloboma also have a condition called microphthalmia. In this condition, one or both eyeballs are abnormally small. In some affected individuals, the eyeball may appear to be completely missing; however, even in these cases some remaining eye tissue is generally present. Such severe microphthalmia should be distinguished from another condition called anophthalmia, in which no eyeball forms at all. However, the terms anophthalmia and severe microphthalmia are often used interchangeably. Microphthalmiamay or may not result in significant vision loss.People with coloboma may also have other eye abnormalities, including clouding of the lens of the eye (cataract), increased pressure inside the eye (glaucoma) that can damage the optic nerve, vision problems such as nearsightedness (myopia), involuntary back-and-forth eye movements (nystagmus), or separation of the retina from the back of the eye (retinal detachment)..

Coloboma

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