Square Incision
Prevent the inner valve from forming a chevron shape with an obtuse angle blade. In addition, a reference line is marked from the tip at the same length as the blade width to help the creation of a square incision.
Ideal Incision Tract
By gradually altering the blade width on the back side with the double bevel, it is easier to cut along the corneal curve until it reaches the corneal stroma, and it is easier to advance parallel to the iris (slightly upward) when perforating the anterior chamber.