Fig. 24. Deep sclerectomy with viscocanalostomy: fornix-based conjunctival flap. After obtaining adequate exposure of the superior limbus, a fornix-based conjunctival flap is dissected. Great care is exercised to avoid trauma to the episcleral vessels during the dissection. If a corneal traction suture is used, the pass should be off to the side of the proposed site to prevent rupture of the limbal tissues.