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Jan 06, 2024

Belt loop technique another option for scleral fixation of bag/lens complex

This month, Cathleen M. McCabe, MD, explains the intricacies of the belt loop

This month, Cathleen M. McCabe, MD, explains the intricacies of the belt loop technique she pioneered to avoid the need for IOL exchange in cases of dislocated in-the-bag IOLs.

Amar Agarwal, MS, FRCS, FRCOphthOSN Complications Consult Editor

Late in-the-bag IOL dislocations are a primary reason for exchanging an IOL. Precipitating factors for dislocation include pseudoexfoliation, prior eye surgery (pars plana vitrectomy), axial myopia, eye rubbing, trauma, capsular phimosis (retinitis pigmentosa), aging, uveitis, previous vitreoretinal surgery, diabetes, atopic dermatitis, previous acute angle-closure glaucoma attack, connective tissue disorders and complicated primary cataract surgery.

Most often, an anterior vitrectomy is required, followed by implantation of a different secondary IOL. This secondary IOL must be supported in the anterior chamber with iris fixation or by a variety of scleral fixation techniques. In 2017, Shin Yamane, MD, published an innovative technique for scleral fixation whereby a three-piece IOL could be supported in the sclera by externalizing the haptics and forming a flange at the end of the haptic with low-temperature handheld cautery. The flange is then buried into the superficial layers of the sclera for stable long-term support of the lens.

This technique has quickly become many surgeons’ go-to method for scleral fixation with a secondary IOL as it avoids the need for a conjunctival perimetry. Sergio Canabrava, MD, was the first to publish using a double-flanged technique with polypropylene suture to fixate a secondary IOL by placing a segment of suture through an eyelet, a fenestration in an IOL or a closed-loop haptic.

To avoid the need for IOL exchange in cases of a dislocated in-the-bag IOL, in early 2019, I began using a modification of the flanged intrascleral haptic fixation technique (Yamane technique) using a piece of 5-0 or 6-0 polypropylene suture to loop around a haptic, through the capsular bag, through the sclera and then anchored on either end by flanges created with handheld cautery creating a "belt loop" method of scleral fixation (Figure 1). The first two cases I treated this way were patients with multifocal IOLs who had a strong desire to keep their original IOL if at all possible. The steps for the belt loop technique are as follows.

1. Mark 2 mm posterior to the limbus in the area of maximal zonulopathy/dislocation and 180° away if placing a paired belt loop (Figure 2).

2. Bend a 30-gauge TSK needle close to the hub.

3. Cut a section of 6-0 polypropylene suture at a bevel and test the suture in the needle lumen to be sure it passes easily (Figure 3).

4. Place one end of the polypropylene suture into the anterior chamber with the end oriented toward the marked axis.

5. Pass the 30-gauge needle just posterior to the spot marked at 2 mm and pass it through the conjunctiva and sclera, behind the capsular bag, and then through the capsular bag between the optic and haptic, close to the optic-haptic junction. Intraocular forceps are often helpful in advancing the needle through the capsular bag (Figure 4).

6. Feed the polypropylene suture into the needle lumen with intraocular microforceps (Figure 4).

7. Withdraw the needle from the eye.

8. Grasp the externalized suture and create a safety flange with low-temperature cautery (large flange).

9. Place the free end of the suture segment through the same incision into the anterior chamber.

10. Pass a second bent 30-gauge needle just anterior to the 2-mm mark, 0.5 mm closer to the limbus than the previous needle pass. Advance the needle through the conjunctiva and sclera and into the sulcus in front of the bag/IOL complex.

11. Feed the trailing end of the suture segment into the needle lumen.

12. Withdraw the needle from the eye.

13. Remove slack and adjust the tension of the suture to center the IOL. When two belt loops are placed, slowly cinch up the loop on either side by withdrawing more suture through the conjunctiva. Tighten alternating sides gradually, watching until the IOL is centered, planar and the appropriate distance from the posterior surface of the iris.

14. Cut the suture 1 mm from the sclera and create small flange with cautery (Figure 5).

15. Repeat externalization of the suture, trimming and formation of a flange as needed until proper positioning is achieved.

16. Push the flange into the superficial sclera using a small instrument such as a Sinskey hook or capsulorrhexis forceps. This is a key step and is facilitated by keeping the flange size relatively small (Figures 6 and 7).

There are various methods for loading the polypropylene suture into the needle lumen.

1. Preload the needle by placing the suture into the needle. The needle is then placed through the sclera, and the suture is advanced into the eye by pushing it further through the needle hub and into the eye. Keep in mind that the suture will be difficult or impossible to advance if the needle is bent.

2. Place a longer (1.25 inch) needle through the sclera and into the anterior chamber and guide the needle tip through a paracentesis with a cannula or intraocular forceps. The suture can then be threaded into the lumen of the needle externally with smooth forceps (Figure 8).

3. Place the suture into the anterior chamber and load it into the needle lumen with intraocular forceps as described above. This is my most commonly used method.

In my practice, I prefer the belt loop method of scleral fixation to recenter and support a dislocated bag/lens complex because it avoids an anterior vitrectomy in most cases, is easily fine-tuned to achieve precise centration, results in stable fixation, does not require special lenses or instruments, and works for all lens designs. It is especially desirable in cases with premium IOLs that the patient would like to retain and in patients with a filtering bleb after trabeculectomy (Figure 9), Xen gel stent (Allergan) or glaucoma drainage device; a scarred conjunctiva after trauma, retinal surgery or strabismus surgery; or difficult to remove lenses such as PMMA or plate haptic lenses.

It is important to create a long tunnel and bury the flange into the superficial layers of the sclera. I have seen in my practice a case of an eroded flange that was too large and not well buried. This is easily treated by trimming, creating a small flange and burying well within the sclera. However, cases of endophthalmitis with flange erosion have been reported. I also caution patients with flanged polypropylene fixation to avoid eye rubbing as this may increase the risk for erosion.

The many variations of Yamane's flanged haptic scleral fixation technique have added a wide range of solutions for stable scleral fixation of secondary IOLs, dislocated bag/lens complexes, and capsular rings and segments, as well as iridodialysis repair. Collectively, these have become my go-to techniques for secure and reproducible scleral fixation. I believe we can all look forward to further innovation in this area in the future.