Nasolacrimal Duct Obstruction Classified by Dacryoendoscopy and Treated With Inferior Meatal Dacryorhinotomy. Part I: Positional Diagnosis of Primary Nasolacrimal Duct Obstruction With Dacryoendoscope

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.