History : Monoka & Masterka

Monoka tm stents are silicone stents used to intubate obstructed nasolacrimal systems.

They are composed of a silicone tube and a punctal plug, similar to that devised by J. Freeman . The punctal plug replaces the sutures that were often considered necessary for securing monocanalicular stents used in lacrimal trauma repair.

J.A. Long has tried to attach the probe to the end of the punctal plug. This type of monocanalicular intubation system was very unstable as the meatus would enlarge very quickly and the tube would extrude.


By repositioning the punctal plug to a 90°angle (1988) to the tube, the stability of the implant was greatly improved and has worked well for monocanalicular intubations (Mini Monoka tm ) and even for intubation through the nasolacrimal duct (Monoka tm) .


Since the initial description  of the Monoka, several improvements have been implemented :


- > Punctal plug :  J.-M. Ruban (Lyon, France) suggested increasing the length of the collarette  from 2 to 4 mm. This has reduced intracanalicular migration almost completely.


- > Guide introducer :

The first Monoka tm stents were composed of a metallic guide probe placed at the end of a silicone tube, just as in all traditional lacrimal probes.


Fabrice Serra (Antibes, France) adapted Jünemann & Büsse's hollow probe technique to the Monoka procedure (Personal communication, 1990). The metallic guide probe was replaced by a prolene thread.

Later, P. Ritleng (Nice, France) designed a slit in the hollow guide probe to facilitate the passage of a prolene thread of varying diameters into the ducts.This permitted a reduction in operating time.




The principle of pushed lacrimal nasal intubation had been proposed many years ago.The technique was simple but the metallic probe (Remky, Veirs...) that remained in place was poorly tolerated by patients.

The excellent tolerance of silicone stents now available clearly compensated for the increased difficulty associated with pulled lacrimal nasal intubation procedures.


The design of a pushed Monoka, Masterka tm,  is really the combination of a venous catheter (e.g. Cathlon tm Quick-Cath tm…)  and a traditional Monoka tm.

The silicone and the anchoring plug remain present, but the metallic guide/introducer is placed inside the silicone stent.

This change allows for monocanalicular nasal intubation to be done without the added difficulty of retrieving the tube from the nasal fossa.