Canaloplasty Surgical Technique

Abstract

The conjunctiva can be opened at either the fornix or the limbus. A rectangular, square or parabolic-shaped scleral flap measuring 5 × 5 mm is then created and includes 1/3 of the scleral thickness (approximately 300 μm, depending on the scleral thickness of the specific eye). In order to reach the Descemet membrane during the dissection of the deeper scleral flap, the superficial scleral flap must be created 1–1.5 mm anteriorly in clear perilimbal cornea. The initial incision is created with a No.11 stainless steel blade (for example, a 15° Slit Knife for paracentesis) or a diamond blade. The flap is created with a ruby blade or a bevel-up crescent knife (for example, a 1 mm Minidisc Ultrasharp knife, Grieshaber Alcon, USA). Then the surgeon performs the sclera-keratectomy, initially creating a small second flap, then the superficial flap, leaving a step of sclera at the edge to allow the tighter closure for the viscocanalostomy/canaloplasty. The scleral flap is then cut towards the cornea, using a ruby blade or a stainless steel crescent knife. The depth of this dissection must extend almost as far as the choroid/ciliary body and is accurately extended anteriorly, keeping the dissection plane as uniform as possible. In the event the suprachoroidal space is opened, the dissection must be continued a few scleral fibers above. The scleral spur is observed when scleral fibers change direction towards a band parallel to the limbus.