Background
An eyelid coloboma is a full-thickness defect of the eyelid. Although an eyelid coloboma can occur in many locations, the most common position is at the junction of the medial and middle third of the upper lid. No lid appendages or accessory structures are usually seen within the coloboma.
Pathophysiology
An eyelid coloboma may occur either congenitally or as a result of trauma (eg, accidental, surgical). An eyelid coloboma is an almost constant feature of Treacher Collins syndrome, which is autosomal dominant with variable penetrance and expressivity.
Upper eyelid coloboma is often associated with cryptophthalmos and, as a result, can occur in any genetic diseases involving cryptophthalmos, including Fraser syndrome (cryptophthalmos syndrome) and Manitoba Oculotrichoanal (MOTA) syndrome. [1, 2]
A case review of upper eyelid coloboma with or without cryptophthalmos included 26 children (age range, 1 d after birth to 15 y). [3] Of these 26 children, 19 had upper eyelid coloboma, 4 had classic cryptophthalmos, and 3 had both eyelid coloboma and cryptophthalmos. Of the 19 cases of upper eyelid coloboma, 5 occurred in isolation, 11 were associated with facial deformities, and 3 were part of a first arch syndrome (according to the Mustarde classification). All cases of classic cryptophthalmos were sporadic and nonsyndromic.
In this case review, Nouby concluded that upper eyelid coloboma with facial deformities and cryptophthalmos could be considered as one anomaly. [3]
Nouby suggested a new grading for this anomaly, as follows [3] :
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Grade 1 - Coloboma without cryptophthalmos
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Grade 2 - Coloboma with abortive cryptophthalmos
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Grade 3 - Coloboma with complete cryptophthalmos
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Grade 4 - Classic cryptophthalmos (absence of all eyelid structures and complete coverage of eye by skin)
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Grade 5 - Severe cryptophthalmos (with severe deformity of the nose and ectropion of the upper lip)
Epidemiology
Frequency
United States
An eyelid coloboma is a rare anomaly.
International
Manitoba Oculotrichoanal (MOTA) syndrome occurs in Aboriginal patients of the Island Lake region of Northern Manitoba. Characteristic findings in patients who are affected include unilateral upper eyelid coloboma or cryptophthalmos with ipsilateral aberrant anterior hairline pattern and anal anomalies. [1, 4, 5]
Mortality/Morbidity
Untreated eyelid colobomas may lead to significant morbidity.
Race
No known racial predilection exists for eyelid coloboma.
Sex
No known sexual predilection exists for eyelid coloboma.
Age
By definition, congenital eyelid colobomas are present at birth.
Prognosis
Prognosis is excellent to good in eyelid colomba, depending on the size of the lesion and the speed of therapy.
Patient Education
Genetic consultation is highly recommended, especially for patients with associated syndromes, such as Treacher Collins syndrome, which is autosomal dominant with variable penetrance and expressivity.
