Fig. 6. Tying a slip knot. The suture needle enters at 1, crosses the incision, and exits at 2. It then re-enters the tissue at 3, a distance of about a 0.25 mm from 2, and in the same direction as the suture is moving. The suture then passes underneath to where the conjunctiva is adherent, such as at the corneoscleral sulcus. The surgeon must be meticulously careful to make sure that the needle is held in a way so that it is advanced in the same plane as the internal and external surfaces and so that it does not exit too soon through the conjunctiva. The needle exits at 4, about 1 to 2 mm in the cornea anterior to the adherence of the conjunctiva at the corneoscleral sulcus. The needle re-enters 0.5 to 1 mm away from point 4, specifically at point 5, and is passed intracorneally a distance of about 3 mm, exiting at 6. At this point, then, the leading end of the suture is at C, and there is a potential loop between 4 and 5, a definite loop between 2 and 3 at B, and the trailing end of the suture is at A.