Fig. 30. Deep sclerectomy with viscocanalostomy: unroofing Schlemm's canal. Unroofing Schlemm's canal is critical to all deep sclerectomy techniques. As the deep flap scleral dissection is carried towards the limbus, a transition zone is found. If in the proper plane with the deep flap dissection, the roof of Schlemm's canal will be found on the back side of the deep flap (black arrow). It is important to look for this transition zone of the smooth endothelial cells of Schlemm's canal as they are in contrast to the rough scleral fibers.