[Surgical technical principles of trans-scleral suture of posterior chamber lenses]

Most reports on transscleral suture fixation of posterior chamber lenses (PCL) do not mention the principal difficulty that the surgeon has no valid information which structures were perforated by the needle and where he happened to fix the PCL loops. To know this exactly is a "conditio sine qua non". Without it, no valid evaluation of longterm results of this method will ever be possible.

Thirtythree PCL were fixated by transscleral suturing. The results of the decisive surgical steps were controlled by intraoperative endoscopy. The experiences and insights gained thereby were used to develop step by step optimal surgical procedures for different conditions. The results of the endoscopically controlled group were compared with the results of 128 eyes with transscleral suture fixation of a PCL without endoscopic control between 6/88 and 4/91.

On the basis of systematically performed endoscopic controls during surgery we have identified several faults and pitfalls which should be avoided. In consequence we have developed rules and items that should be fulfilled in order to arrive at an anatomically correct position of the PCL: 1. The transscleral suture should only penetrate the sulcus and no adjacent structures of the iris or the ciliary processes. 2. The PCL loops must be primarily directed into the sulcus, 3. PCL design must be adapted to the anatomical needs of the procedure and must provide a safe distance between iris and PCL to avoid iris-shafting. Detailed suggestions are given to fulfil these requirements. The most important point is the two-step implantation of the PCL out of the anterior chamber into the posterior chamber to avoid a steep and disadvantageous implantation angle. Up to date, no cases with chronic intraocular inflammation have occurred in the endoscopically controlled group in contrast to the earlier non-controlled group.

Our results allow--even without endoscopic control--an exact positioning of the PCL hepatics in the sulcus, which is the most important step in the whole procedure. However, for a scientific evaluation of longterm results after transscleral suturing of PCL endoscopic control will further be needed to demonstrate or to rule out any potentially harmful compression of the ciliary body or iris structures and to see whether or not such irregularities will be associated with reduced longterm tolerance.