Surgical technique . The procedure can be split into the following steps:

1. Create a 1.6–1.7 mm clear cornea temporal incision parallel to the iris.

2. Introduce low resting molecular weight cohesive VES into the AC to facilitate the entrance of the handle: with this maneuver, the surgeon must avoid the creation of air bubbles in the AC that may obstruct the visualization of the camerular angle.

3. Position the goniolens on the cornea and control the vision of the angle. Normally, a modified Swan-Jacobs lens is applied.

4. Remove the goniolens and insert the tip of the handle in the AC.

5. Progression of the tip in a nasal direction inside the AC, reposition the goniolens and activate the continuous irrigation (red arrows exiting the probe) (Fig. 9.2).

6. Insert the tip in the Schlemm Canal anterior to the scleral spur through the trabeculate in the nasal sector and successive ablation, first in a clockwise and then in an anticlockwise direction with the assistance of a fulcrum point.

7. Ablate a strip of trabeculate and the internal wall of the Schlemm Canal for 60°–140°, depending on the patient’s IOP, under direct gonioscopy control. As mentioned earlier, one part of the tip easily enters the trabeculate and the other slides easily into the Schlemm Canal. The trabecular and juxtacanalicular tissues are ablated during the movements inside the Schlemm Canal. The ablated tissue is aspirated immediately (red arrow entering the probe). If the surgeon has decided to perform a 30° ablation, starting from a specific point, he performs the ablation for 30° in one direction to remove the trabeculate, and then performs the same maneuver for 30° in the opposite direction. The entire maneuver is performed extremely slowly and carefully. Intraoperative reflux of blood may be observed during this phase through the solution of continuity created; many authors believe that this is a positive sign as it confirms the ab interno unroofing of the Schlemm Canal. The probe is set at 0.7–0.9 W (range 0.5–1.5 W) and successively regulated with variations of 0.1, depending on the results achieved. The target tissue is destroyed by applying a series of energy bursts of high peak power and low duty-cycle. This destroys the tissue without generating a considerable amount of heat, as happens with normal cauterization of blood vessels. If the surgeon observes tissue being burned, the power should be set at a lower level; on the other hand, the power level must be increased if the surgeon wishes to remove a greater amount of the trabeculate.