coloboma

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coloboma

 [kol″o-bo´mah] (pl. colobomas, colobo´mata) (L.)
1. a defect of tissue.
2. particularly, a defect of some ocular tissue, usually due to failure of part of the fetal fissure to close; it may affect the choroid, ciliary body, eyelid (palpebral coloboma, colobo´ma palpebra´le), iris (colobo´ma i´ridis), lens (colobo´ma len´tis), optic nerve, or retina (colobo´ma re´tinae). A scotoma is usually present, corresponding to the area of the coloboma.
Coloboma of the iris. From Dorland's, 2000.

col·o·bo·ma

(kol-ō-bō'mă),
Any defect, congenital, pathologic, or artificial, especially of the eye due to incomplete closure of the retinal fissure.
[G. kolobōma, lit., the part taken away in mutilation, fr. koloboō, to dock, mutilate]

coloboma

/col·o·bo·ma/ (kol″o-bo´mah) pl. colobomas, colobo´mata   [L.]
1. an absence or defect of tissue.
2. a defect of ocular tissue, due to failure of part of the fetal fissure to close; it may affect the choroid, ciliary body, eyelid, iris, lens, optic nerve, or retina.

bridge coloboma  coloboma of the iris in which a strip of iris tissue bridges over the fissure.
Fuchs' coloboma  a small, crescent-shaped defect of the choroid at the lower edge of the optic disk.
coloboma lo´buli  fissure of the ear lobe.

coloboma

(kŏl′ə-bō′mə)
n. pl. colobo·mata (-mə-tə)
An anomaly of the eye, usually a developmental defect, that often results in some loss of vision.

col′o·bo′ma·tous adj.

coloboma

[kol′əbō′mə] pl. colobomas, colobomata
Etymology: Gk, koloboma, defect
a congenital or pathological defect in the ocular tissue of the body, usually affecting the iris, ciliary body, or choroid by forming a cleft that extends inferiorly. Colobomas are usually the result of the failure of part of the fetal fissure to close. colobomatous, adj.
enlarge picture
Coloboma

col·o·bo·ma

(kol'ō-bō'mă)
Any defect, congenital, pathologic, or artificial, especially of the eye due to incomplete closure of the optic fissure.
[G. kolobōma, lit., the part taken away in mutilation, fr. koloboō, to dock, mutilate]

coloboma

A congenital gap in a part, especially in the IRIS or CHOROID of the eye or in an eyelid.

coloboma 

Congenital, pathological or operative anomaly in which a portion of the structure of the eye is lacking, e.g. coloboma of the choroid, coloboma of the eyelid, coloboma of the iris, coloboma of the lens, coloboma of the retina, etc. Typical colobomas result from defective closure of the embryonic fissure of the optic cup. Congenital iris colobomas are usually located inferiorly. They are often associated with Crouzon's syndrome (Fig. C13). Lid colobomas are commonly associated with Treacher-Collins syndrome. Coloboma of the optic disc is characterized by a glistening, white excavation, decentred inferiorly. It is sometimes confounded with glaucomatous cupping, especially when it is accompanied by a field defect. The condition is often associated with microphthalmia and several syndromes (e.g. Edward's syndrome, Patau's syndrome).
Fig. C13 Coloboma of the irisenlarge picture
Fig. C13  Coloboma of the iris

coloboma

an apparent absence or defect of some ocular tissue, usually due to failure of a part of the fetal fissure to close; it may affect the choroid, ciliary body, eyelid (palpebral coloboma, coloboma palpebrale), iris (coloboma iridis), lens (coloboma lentis), optic nerve or retina (coloboma retinae). Colobomas of the choroid are common in cattle, and have been observed in miniature swine. Colobomas of the optic disk are an inherited defect in several breeds of cattle.

atypical coloboma
on occurring at a location other than the fetal fissure.
iris coloboma
a full thickness defect in the iris. When it occurs at the base of the iris, it is called iridodiastasis.
optic nerve coloboma
part of the scleral ectasia syndrome in dogs; also seen in Basenji dogs and Charolais cattle.
typical coloboma
one occurring in or near to the fetal cleft.

Patient discussion about coloboma

Q. My grandson 5mths has been dignosed with Coloboma HAs anyone had any experiences with this. He will be seen at Toronto Hospital for Sick Kids

A. Don't have it or a child with it, so I can't add from my own experience. However, here are several places in which you can find more information about this:

http://en.wikipedia.org/wiki/Coloboma
http://www.nlm.nih.gov/medlineplus/ency/article/003318.htm

More discussions about coloboma
References in periodicals archive ?
David (a pseudonym) was an older adolescent who exhibited many major features of CHARGE syndrome including coloboma of the eye, heart defect, choanal atresia, ear anomalies, and small stature, as well as a cleft palate and facial paralysis.
The functional implications of vision loss are dependent on the location of the coloboma (Smith et al.
The nonrandom association of coloboma, choanal atresia, retardation of growth and development, and genital and ear anomalies are frequently present in various combinations and degrees in individuals with CHARGE syndrome (Tegay & Yedowitz, 2009).
They can be idiopathic, hereditary or associated with systemic and metabolic conditions such as galacatosaemia, Down's syndrome, interauterine infections such as rubella, and ocular diseases such as aniridia, coloboma and Peter's anomaly.
Ocular examination should include assessment of visual function, nystagmus, strabismus, the presence or absence of a red pupillary reflex, IOP, corneal diameter and co-existing ocular conditions such as persistent hyperplastic primary vitreous and coloboma (see later).
Which of the following statements about colobomas of the optic nerve is TRUE?
Those with systemic associations include optic disc coloboma (including the morning glory anomaly), optic disc hypoplasia, megalopapilla, peripapillary staphyloma, and optic disc dysplasia.
5 inclusive setting Primary language used English English at school Primary language used English English at home Parent interviewed Mother Mother Demographic characteristic Eric Age 7 Grade K/1 Gender Male Condition Wolf Hirschhorne syndrome (4P), multiple disabilities Hearing loss Mild to moderate Visual diagnosis Colobomas Learning modality Visual learner Additional disability Yes Communication mode Nonverbal, gestures School placement Inclusion Time in this school 3 years placement Previous placement Inclusion Daily hours in the 6 inclusive setting Primary language used English at school Primary language used English at home Parent interviewed Mother Table 2 Strategies used by the inclusion facilitator.
Her visual impairment was due to bilateral chorioretinal colobomas and microphthalmia, and her visual acuity was listed as 20/960.