Novel device for expanding Schlemm's canal: a morphological study: Implantation of the Stegmann Canal Expander following viscodilation of Schlemm's canal resulted in permanent expansion of the canal lumen and distension of the trabecular meshwork without complications.

This study was performed to assess any changes in Schlemm's canal (SC) in human autopsy eyes possibly resulting from the injection of a viscoelastic substance and implantation of a new device (the Stegmann Canal Expander, SCE) into SC. After the surgical procedure, eyes were fixed, dissected into quartered segments and examined using light and scanning electron microscopy. Tissue sections displayed a marked dilation of SC and of the collector channels compared with untreated control sections. The SC walls were disrupted in some areas due to viscodilation, but not due to SCE implantation. In all eyes, the entire 9-mm length of the SCE was positioned inside the canal, keeping the canal wide open. The SCE diameter of 240 μm remained unchanged after implantation. Injection of a viscoelastic substance into SC leads to marked dilation of SC and collector channels. Implanting the SCE into SC allowed persistent expansion of SC and stretching of the trabecular meshwork. This may increase the permeability of the trabecular meshwork, reduce its resistance to aqueous humour and maintain circumferential flow within SC. Experimental and clinical studies should determine the impact of this new canal expander in terms of lowering intraocular pressure in glaucoma surgery. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.