Biodegradation of silicone drainage tubes in the efferent lacrimal system

The authors present an account on their experience with biodegradation of silicone cannulas used for drainage of the efferent lacrimal system. They examined by means of a light microscope (enlargement up to 140 x) 38 cannulas, inserted into the lacrimal pathways for 1-7 months. They did not observe any biological damage of the surface of the cannula, not even when compared with non-exposed cannulas. Microbiological examination of six exposed cannulas did not reveal fungal infestation. The lacrimal pathways are not an aggressive environment for temporary cannulas.