Rectangular loop suture to correct iris capture of the posterior chamber intraocular lens

In eyes with a capsular defect, intracapsular intraocular lens (IOL) implantation is not possible. Accordingly, several alternative surgical techniques can be applied, including transscleral IOL fixation, sutureless intrascleral fixation, and the scleral hook technique [1‐3]. While these have proven to be safe and effective, some complications remain, including suture breakage, IOL tilt or dislocation, haptic slip, and iris capture [4‐6]. Cho and Yu reported an incidence of iris capture of 23% in patients who underwent combined scleral IOL fixation and pars plana vitrectomy. Iris capture leads to blurred vision, photophobia, and dull pain. Moreover, iritis and secondary glaucoma may occur during long-term iris capture [7].

Iris capture of the IOL may be caused by pupil dilation [8], IOL deviation or tilt, a floppy iris [9], or reverse pupillary block [10]. Although pupil dilation or laser iridotomy of a reverse pupillary block are useful for iris capture, their success rates are relatively low [11‐13]. When iris capture is not resolved by these techniques, surgical techniques can be applied, including IOL repositioning [12] and exchange [14]. However, these surgeries cause relatively large injuries and can result in bleeding and corneal endothelium loss. We performed a minimally invasive technique for three cases, and no iris recapture was observed post surgery.

Iris capture is a common complication of IOL implantation for eyes with a capsule defect. It may be related to pupil dilation, IOL deviation or tilt, a floppy iris, or reverse pupillary block [8‐10]. Mydriasis and subsequent miosis can release the iris capture, but recurrence is not uncommon, as seen in the right eye of case 1. Choi et al. [12] reported laser iridotomy as one treatment for iris capture, however, with only a 60% success rate. Moreover, surgical techniques are available for failed cases, which include the previously described strategies of IOL repositioning and IOL exchange. In Choi et al.’s study, IOL repositioning was used in 10 eyes, but was successful in only 4 eyes. In one of the failed eyes, the IOL was subluxated and subsequently treated by refixation, but iris capture was still present. A similar case was presented in the present report (left eye of case 1). The IOL was moved from 2 mm behind the limbus to 3.5 mm by an intrascleral fixation technique. However, iris capture reoccurred after this surgery. This failure may have been related to the relaxed iris and increased pupil size under dark conditions. IOL exchange is not commonly used because of the resulting large injuries. Yoo et al. reported a new IOL transscleral suture fixation technique, which they named the H technique [15]. The suture forms a barrier between the lens and the iris to avoid postoperative iris capture, the incidence of which was 2.5%. However, a complication of their technique must be considered, whereby the direction of the H suture was fixed and unchangeable after IOL fixation, such that iris capture may occur at the point where no suture passes.

The new rectangular loop suture technique prevents iris recapture by forming a barrier between the IOL optic and the iris, which is similar to H technique. However, with a well-designed suture direction, our technique is more individualized and precise. The applied direction was calculated according to the appearance of the iris capture before the surgery, as shown in Fig. 1. In case 1, we found that the iris capture tended to occur repeatedly in the same region of the iris, thus the suture was designed to pass behind this part of iris to prevent recurrence. However, more cases should be observed to verify this hypothesis. This technique can also correct the IOL rotation around the coronal axis by the contact between sutures and IOL optic. However, it is incapable to correct the other types of IOL dislocation.

Rho et al. [16] evaluated the influence of across-pupil sutures on the IOL optical quality and found no difference with or without sutures. In the present cases, the distance between two sutures was 3–4 mm, avoiding the central region of the pupil, thus no abnormal vision problems occurred post surgery.

During the operation, adequate attention should be focused on the IOP. When the pressure is insufficient during suturing, a large astigmatism will occur post surgery because of intraocular pressure recovery and the tightness of the suture. Astigmatism will decrease within several months, as shown in case 1.

Our minimally invasive technique of rectangular loop suture can efficiently solve the complication of iris capture and is easy to perform.