title: Can congenital nasolacrimal-duct obstruction interfere with visual development? A cohort case control study.
abstract: OBJECTIVE
  To ascertain if tear film disturbance in congenital nasolacrimal-duct obstruction (CNLDO) interferes with visual maturation.
  
  
  METHODS
  Review of a cohort of children in which the occurrence and duration of CNLDO had been previously documented. Information obtained included acuity, refractive data, and presence or absence of strabismus. The incidence of abnormality in the CNLDO group was compared with that in controls, which were fellow eyes in those children with unilateral obstruction, and all children with no history of CNLDO.
  
  
  RESULTS
  Of 4792 children, visual acuity data were obtained on 2249. There was no difference in the incidence of amblyopia in CNLDO children compared with controls (p < 0.89) nor in the watering eye compared with the fellow eye (p < 0.58). No correlation between refractive error or astigmatism and CNLDO (p < 0.26 and p < 0.32 respectively) was found. Strabismus was no more common in CNLDO than in controls (p < 0.89).
  
  
  CONCLUSIONS
  This study found no evidence to suggest that visual maturation is adversely affected by allowing spontaneous resolution of CNLDO.
authors.affiliation: University Department of Ophthalmology, Ninewells Hospital, Dundee, Scotland.
authors.forename: J D
authors.initials: JD
authors.lastname: Ellis
authors.forename: C J
authors.initials: CJ
authors.lastname: MacEwen
authors.forename: J D
authors.initials: JD
authors.lastname: Young
mesh_terms: D000550:Amblyopia / Q000209:etiology; D016022:Case-Control Studies; D002648:Child; D002657:Child Development; D015331:Cohort Studies; D006801:Humans; D007766:Lacrimal Apparatus Diseases / Q000150:complications / Q000151:congenital / Q000503:physiopathology; D009301:Nasolacrimal Duct; D012030:Refractive Errors / Q000209:etiology; D013285:Strabismus / Q000209:etiology; D014786:Vision Disorders / Q000209:etiology*; D014792:Visual Acuity / Q000502:physiology