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We have read with avid interest the article on external dacryocystorhinostomy (DCR) for partial nasolacrimal obstruction (PNLO) in adults.1 We would like to clarify a few pertinent aspects which are of relevance in understanding this rather complex issue.
Firstly, we are not in consonance with the authors' definition of PNLO, which they define as “a freely patent nasolacrimal system to irrigation with minimum or no reflux from the upper canaliculus or punctum.” In our clinical experience and as quoted in the literature, a patient is usually diagnosed as having PNLO if there is a relative resistance to passage of fluid on irrigation2 along with some degree of reflux thorough the opposite punctum.3 So, the use of the term “freely patent” may not be appropriate to describe PNLO.
Secondly, although we agree that most patients with PNLO may eventually require a DCR the importance of giving a thorough trial to less invasive treatments such as forced syringing, stents, balloon dacryoplasty, and silicone intubation before undertaking a DCR in such cases has not been adequately emphasised. It is true that variable results have been reported with these techniques but there are studies which show success rates as high as 73.3% with antegrade balloon dilatation combined with silicone intubation even in cases of complete nasolacrimal obstruction over a 1 year follow up.4
We would like to share with the readers our own experience in handling such cases where we routinely use a procedure of dilatation of the nasolacrimal duct with lacrimal probes of progressively increasing diameters, taking care not to damage the puncta. During probing, we augment its effect by employing a technique which we call “reaming” of the nasolacrimal duct, which involves rotating the proximal end of the probe in circles of increasing diameter, which translates into a similar movement of its distal end. This is followed by silicone intubation. This is a safe and simple procedure which gives results comparable to balloon catheter dilatation and can be adopted by centres in the developing world that do not have access to expensive treatments and instrumentation.