title: Nasolacrimal duct obstruction classified by dacryoendoscopy and treated with inferior meatal dacryorhinotomy. Part I: Positional diagnosis of primary nasolacrimal duct obstruction with dacryoendoscope.
abstract: OBJECTIVE
  To investigate the site of primary nasolacrimal duct obstruction (PNLDO) using a dacryoendoscope and nasal endoscope.
  
  
  METHODS
  Retrospective, observational case series.
  
  
  METHODS
  After local anesthesia, dacryoendoscopy and nasal endoscopy were performed in 149 cases (138 Japanese subjects) of PNLDO. Membranous nasolacrimal duct obstruction was termed as lower PNLDO, and occlusion at sac/duct junction termed as higher PNLDO.
  
  
  RESULTS
  The incidence of lower PNLDO was 26.8% (40 of 149 cases), and 109 cases (73.2%) were diagnosed with higher PNLDO.
  
  
  CONCLUSIONS
  The dacryoendoscope is extremely useful to observe directly and evaluate the site of obstruction with accuracy in PNLDO. The higher and lower PNLDO may have a different etiologies.
authors.affiliation: Department of Ophthalmology, Kanazawa University School of Medicine, Kanazawa, Ishikawa 920-8641, Japan. sasatsug@med.kanazawa-u.ac.jp
authors.forename: Tsugihisa
authors.initials: T
authors.lastname: Sasaki
authors.forename: Yuuko
authors.initials: Y
authors.lastname: Nagata
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Sugiyama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003608:Dacryocystorhinostomy; D003941:Diagnostic Techniques, Ophthalmological; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D015994:Incidence; D007767:Lacrimal Duct Obstruction / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009301:Nasolacrimal Duct / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D011859:Radiography; D012189:Retrospective Studies