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Transscleral suturing is a standard technique to fix various intraocular implants in the sulcus. Since the early 1990s, the ab-externo technique of Lewis 1 and the refined ab-interno technique of Smiddy et al 2 are the basis for multiple variations in transscleral suturing. However, all techniques need a reliable external fixation in the sclera without direct knot exposure. Leaving a suture knot directly under the conjunctiva often leads to suture erosion and consecutively to an elevated risk for endophthalmitis ( figure 1 ). Therefore, it is generally recommended that the knot be protected, for example, by burrowing it under a scleral flap. 3 However, late atrophy of the scleral flap is often observed in the long-term and causes late suture erosion through the conjunctiva. 4 Alternative techniques by creating a scleral groove or a scleral pocket are less invasive, but share the same limitations. 5-8
We present a completely knotless technique (Z-suture) that is fast, easy to perform and suitable for transscleral suture fixation of various intraocular implants regardless of the type of implant or the suturing technique used.
Surgical technique
Various implants were placed in the sulcus and sutured transsclerally. Foldable intraocular lenses (IOLs) (AF-1; Hoya, Frankfurt, Germany) were fixed using a modified ab-externo technique with a double-armed 10-0 polypropylene suture as described previously. 9 Other implants, such as the artificial iris prosthesis (HumanOptics, Mannheim, Germany), open iris diaphragm (PD1; Acri.Tec, Glienicke b., Berlin, Germany) and closed iris diaphragm (ID1; Acri.Tec), were fixed using the ab-interno technique with three single-armed looped 10-0 polypropylene sutures with a slip knot. 10
All manoeuvres finally resulted in two (IOL) or three (artificial iris prosthesis and iris diaphragms) sutures emerging from the outer sclera ( figure 2A ).
In all cases, external suturing was performed with a new knotless Z-suture technique: The external suturing was started with an intrascleral pass adjacent to the transscleral penetration site parallel to the limbus. This intrascleral pass was repeated in the respective opposite direction ( figure 2B ) finally resulting in a zigzag pattern with five indentations ( figure 2C ). Each pass (3-4 mm) should start directly beneath the exiting site. With each pass the resistance force increased and, once the five zigzag passes were done, the suture was cut...