title: The incidence, embryology, and oculofacial abnormalities associated with eyelid colobomas.
abstract: OBJECTIVE
  To describe a cohort of patients with congenital eyelid coloboma, to identify associated ocular and craniofacial abnormalities, and to establish any correlation between the size and location of eyelid colobomas and the presence of such abnormalities.
  
  
  METHODS
  An observational case series of 55 patients with eyelid coloboma treated by a single surgeon (JROC) between 1985 and 2005.
  
  
  RESULTS
  Eyelid colobomas predominantly affected the upper lids (93%), and were typically unilateral (76%). About a third (29%) were an isolated finding, with the remainder associated with other ocular (62%) and/or craniofacial (53%) abnormalities. Of those with ocular abnormalities; 19 (56%) had conjunctival traction bands, 16 (47%) choristomas, and 8 (24%) an abnormal globe. Of those with craniofacial abnormalities; 13 (45%) had Goldenhar Syndrome, 10 (35%) clefting disorders, and 4 (14%) Fraser Syndrome. Clefting disorders were typically associated with more severe colobomas and a higher incidence of conjunctival traction bands, first arch syndromes with smaller colobomas and more choristomas. Overall large colobomas were significantly associated with the presence of other craniofacial defects compared with small colobomas (P<0.01, χ(2)), but coloboma size did not correspond with the presence of other ocular abnormalities.
  
  
  CONCLUSIONS
  Coloboma size, location, and associations in this series are consistent with our current understanding of eyelid embryogenesis. It is likely that those colobomas associated with other craniofacial and ocular abnormalities are those which result from errors earlier in embryogenesis during eyelid specification, growth, and closure, whereas isolated colobomas arise later during eyelid separation, and after codependent structures have developed.
authors.affiliation: Adnexal Service, Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK.
authors.forename: H B
authors.initials: HB
authors.lastname: Smith
authors.affiliation: Adnexal Service, Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK.
authors.forename: D H
authors.initials: DH
authors.lastname: Verity
authors.affiliation: Adnexal Service, Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK.
authors.forename: J R O
authors.initials: JR
authors.lastname: Collin
mesh_terms: D000015:Abnormalities, Multiple; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003103:Coloboma / Q000196:embryology / Q000453:epidemiology; D019465:Craniofacial Abnormalities / Q000473:pathology*; D005124:Eye Abnormalities / Q000473:pathology*; D005143:Eyelids / Q000002:abnormalities*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012189:Retrospective Studies; D013577:Syndrome; D055815:Young Adult