A major concern of sutured IOLs is suture breakage, biodegradation, loosening, slippage, or inadvertent cutting of the sutures resulting in late IOL dislocation. Suture breakage was reported to occur in up to 6 % of cases in 5 years’ time, and higher rates (up to 24 %) in pediatric patients with a long life-expectancy and longer follow-up periods [17–20]. We described a series of seven events of late IOL subluxation, 3–9 years after trans-scleral fixation, in three individuals. The 10–0 prolene sutures breakage occurred in both eyes of the same patient operated years apart, and even in two different locations in the same eye [21]. All of these cases occurred in young patients in their 20s, with similar pathology (primary familial bilateral ectopia lentis), and in all cases, the sutures were threaded through fixation holes of PMMA lenses. In contrast, in hundreds of other cases we did not experience suture breakage; thus, the cause of suture breakage in these specific cases is still unknown.

Commonly used sutures for IOL fixation are 10–0 and the thicker and stronger 9–0 polypropylene suture (60 % more tensile force than 10–0 prolene). Polyester (Mersilene), polytetrafluoroethylene (Gore-Tex, Ethicon, Inc.), or steel sutures were also described as suture materials [22, 23]. Gore-Tex material is extremely durable; however, the smallest available suture is 8–0, and it is not registered for intraocular use.

Suture erosion and exposure causes patient discomfort and bares the risk of endophthalmitis [24]. This complication may be prevented by suture knot burial or by covering the knot under a partial thickness scleral flap, although suture exposure through the scleral flap has been described [25].

Additional complications associated with trans-scleral fixation of posterior chamber IOLs are tilt or decentration of the lens, late IOL dislocation, glaucoma, CME, and intraocular or suprachoroidal hemorrhage [25, 26].

Lens decentration, IOL tilt, and suture exposure are not uncommon. This can be consistently prevented by utilizing a combined iridoscleral fixation technique. The PC-IOL is first sutured to the scleral wall using any of the previously described techniques. Then, the pupil is pharmacologically constricted, and the IOL optic is prolapsed anteriorly to create an iris capture. The IOL haptics are then sutured to the iris in a regular fashion (Fig. 25.2). This may take a few more minutes; however, surgery is safe and quite simple. The four-point fixation provides better stability and centration; the IOL weight is distributed to four sutures, and if one suture breaks or is removed, the IOL is still stable. We have adopted this approach for many years and find it extremely efficient [27]. In a series of cases operated between 2000 and 2007, combined iridoscleral fixation was done in 34 eyes of 25 patients, 9 of them bilaterally. Almost one-half (44 %) were children younger than 18 years. Stable long-term fixation was evident in all cases with a low rate of complications, the most common of which was iris capture (18 %) [28]. Since then, we have performed numerous such combined operations with very satisfactory long-term results, and this is now our preferred technique.

In summary, in the absence of capsular support, scleral fixation of posterior chamber intraocular lenses is an efficient alternative. Combined iridoscleral fixation may provide extra safety and low rate of complications.