CAPSULAR MEMBRANE SUTURE FIXATION OF IOLS

Howard V. Gimbel, MD, MPH and Hala Marzouk, MD

There has been tremendous progress in cataract surgery since intraocular lens (IOL) implantation and phacoemulsification have become well established. The combination of a circular anterior capsule opening, nucleofractis phacoemulsification, and in-the-bag placement of an IOL represents the standard of care for cataract surgery.¹

The desired outcome of IOL implantation is a well-centered and stable lens that enhances vision while avoiding corneal and uveal touch. In the absence of in-the-bag fixation, this outcome can be achieved with optic capture by an anterior, a posterior, a combined anterior and posterior continuous curvilinear capsulorrhexis (CCC), or an opening in a capsular membrane. Capsular membrane suture (CMS) fixation is a technique used to fixate mobile or decentered sulcus IOLs when membrane optic capture is not an option. CMS fixation extends the advantages of IOL to capsule fixation when otherwise in-the-bag fixation is compromised and membrane optic capture is impossible. CMS may also be used to center and fixate subluxated IOLs that are in the capsular bag when there is good fibrosis around the CCC.

Implantation of an IOL does not always ensure a stable long-term postoperative course. Subluxation or dislocation of the IOL may occur after uncomplicated cataract surgery, with an incidence ranging from 0.2% to 3.0%.^2–6 A subluxated IOL can be classified as out-of-the-bag, in-the-bag, or part-in- and part-out-of-the-bag.

Several options to secure decentered or subluxated IOLs have been described, including iris-sutured posterior chamber IOLs (PCIOLs),^7,8 scleral-sutured PCIOLs,^7–15 and IOLs with haptics tunneled within the sclera.¹⁶ Recently, an anchoring device that grasps the edges of the capsulorrhexis and is secured to the scleral wall has been successful in experimental models.¹⁷

In this chapter, we will present a number of clinically established techniques that use the capsule itself to anchor, center, and stabilize the IOL.

Capsular Membrane Suture Fixation (of a Subluxated Sulcus-Placed IOL)

This technique, described by Gimbel et al in 2008,¹⁸ involves suturing the lens haptics to the remnant capsular membrane in order to achieve capsular membrane fixation of the IOL.

SITUATIONS AND INDICATIONS FOR CAPSULAR MEMBRANE SUTURE FIXATION

Out-of-the-Bag IOL Fixation or Repositioning

An out-of-the-bag IOL subluxation most commonly arises from sulcus placement of a PCIOL because of a posterior capsule rupture. Possible underlying mechanisms include an inadequate IOL length for a large sulcus diameter, a localized zonular defect, haptic damage, or haptic memory loss. Whether the anterior capsulorrhexis is intact or not, subluxation of the IOL may be caused by one haptic placed in the bag and the other left in the sulcus. Decentration is aggravated by late capsular contraction. The IOL may be stable but decentered and will need to be released into the sulcus in the process of surgical repair. In addition to these cases of severely damaged capsular bags or misplaced haptics, a central opening in a capsular membrane that is too large for optic capture poses another challenge for capsule fixation of the IOL. A peripheral fibrotic membrane makes capsular membrane fixation by sutures possible and avoids many of the complications of other techniques.

Aphakia is seen less frequently now than in the past, but it may occasionally present in patients who are aphakic due to pediatric or adult extracapsular cataract surgery without an IOL, trauma repair without an IOL placed, and complications during previous cataract surgery preventing placement of an in-the-bag IOL. Several options have been discussed in the literature to secure secondary IOLs in this context,19 including anterior chamber IOLs, iris-sutured PCIOLs,^14,20,21 scleral-sutured PCIOLs,^14,21,22 and IOLs with haptics tunneled within the sclera.²³ When a capsular membrane has formed with the capsule or capsule remnants well supported by zonules and fixation by membrane optic capture cannot be used, the IOL may be fixed to the capsular membrane by suturing the haptics to the membrane. This type of fixation has the advantage of stability, excellent optic centration, and fewer possible complications compared with other procedures.

If a large, thick Soemmering ring is present and is not emptied, the haptics in the sulcus would be pressed against the iris, possibly causing pigment dispersion. The bag may be opened and allow placement of the haptics in the reopened capsular bag. If this is not possible and the capsule has enough fibrosis, the haptics may be sutured to the membrane. Alternatively, a central opening may be made in the capsule, if one is not already present, for membrane optic capture.

IOL Replacement and Fixation

If a defective or pitted IOL optic can be removed through the original capsular opening, the haptics of the IOL may be removed from a fused capsular bag by sliding them out of the membrane. If this is not possible because of designed bends or loops on the haptic, the haptics may be amputated from the optic and left in the membrane. A similar removal technique may be used for an eccentric IOL with only one loop in the bag. Undersized sulcus-based IOLs with neither haptic in the capsular bag may be mobile, leading to uveitis-glaucomahyphema syndrome and requiring surgical intervention.^24,25 These surgical challenges lend themselves to secondary surgical fixation techniques, either capsular membrane optic capture²⁶ or the technique described herein of suturing the IOL haptics to the membrane to ensure centration and fixation of the IOL.

SURGICAL TECHNIQUE (FOR AN INFERIORLY SUBLUXATED IOL)

1. Preparation and draping is done in the usual, sterile manner. Local anesthesia drops are instilled. Any posterior displacement of the IOL, indicative of zonular laxity, should be noted.
   
2. The white-to-white corneal diameter is then measured using calipers in case of possible need for an anterior IOL placement. For exposure and suture passes, limbal paracenteses are made at the 1:00, 3:00, 4:30, 6:00, 7:30, 9:00, and 11:00 positions using a paracentesis diamond knife (Mastel Precision G1521). Intracameral anesthesia is obtained with approximately 0.5 mL of preservative-free lidocaine 1%. Grieshaber iris hooks (Alcon Laboratories, Inc) are placed through the paracentesis sites to capture the edge of the iris to fully expand the pupil in a pentagonal configuration.
   
3. A 2.0-mm clear corneal incision is formed inferotemporally at the 5:00 position using a keratome blade. An ophthalmic viscosurgical device (OVD) is selected. A cohesive, high molecular weight OVD such as Healon5 (Johnson & Johnson Vision) is better in maintaining the anterior chamber during the surgery. Grieshaber scissors may be used to cut posterior synechiae where necessary. Using a Sinskey hook, the decentered sulcus IOL is manipulated and centered in the pupil on the capsular membrane.
   
4. Suturing of the lens to the capsule is done using 10-0 Prolene suture (90916; Ethicon) on a taper-cut, 13.0-mm needle (CIF-4; Ethicon). The needle is passed through the paracentesis at the 3:00 position then through the capsular membrane posterior to the inferonasal haptic, then out of the capsule, and then finally out of the eye at the paracentesis at the 7:30 position using a 26-gauge cannula to guide it. The needle is cut and removed from the 10-0 Prolene suture.
   
5. Next, both ends of the suture are drawn out through the main incision using a cyclodialysis spatula and a Sinskey hook, and a knot is formed outside of the incision. Using a Y-hook, the first half hitch of the knot is slid carefully until it is snug against the capsular membrane. Care has to be taken to exert the least amount of tangential traction when tying the sutures to avoid tearing the capsular membrane. Three additional ties may be applied using the same technique to secure the knot. The knot may be tied using the Siepser technique,²⁷ but the IOL haptics may also be sutured onto the capsular membrane using the previously placed clear corneal incision needed for OVD removal. Healon5 should be instilled as necessary to maintain the anterior chamber. The suture tails are cut using Gills-Welsh or other microscissors. The suture has thus effectively tied the haptic of the IOL to the capsular membrane. The same technique is used to secure the superotemporal haptic to the capsular membrane. Stable fixation of the IOL to the capsular membrane may be confirmed by gently tapping the lens with a spatula or a Sinskey hook.
   
6. At the end of the surgery, Healon5 is replaced with balanced salt solution, stromal hydration of the wound edges is done, and the wounds are confirmed to be watertight, requiring no sutures. Topical antibiotic/steroid drops are instilled (Figure 25-1 and Videos 25-1A and B).

• Domingues et al suggested placing the sutures through 2 micro circular capsulorrhexis openings in the capsule, each with the diameter of 1 mm, made in the remnants of the anterior capsule.28 These holes will be fashioned where haptics are fixated. We suggest that holes are not possible and are not necessary in a fibrotic membrane because a fibrotic membrane resists tearing where the suture needle passes.
  
• Intraoperative tearing or cheese-wiring is a possibility, though it was not seen in any of our patients.²⁹ Should cheese-wiring occur, the area of capsule adjacent to the fibrosis is more likely to tear than the actual fibrosis itself. The least amount of tangential tension necessary should be used in securing and centering the IOL. Similarly, postoperative cheese-wiring of the capsule by the 10-0 or 9-0 polypropylene suture is a potential risk. This risk, however, is likely minimal given that postoperative capsular remodeling and fibrosis may serve to keep the attachment firm and secure. In addition, the fact that the IOL is directly attached to the capsular bag and not to adjacent structures, such as the iris or sclera, poses a decreased risk of late IOL subluxation or dislocation due to ocular movement and tissue erosion. This is because in CMS fixation, the zonular apparatus, rather than the suture itself, is chiefly responsible for IOL centration and stability.
  
• The membrane-sutured lens does not require a normal anterior chamber angle and also avoids the potential of corneal endothelial cell loss with corneal decompensation over time, intraocular inflammation, pigment dispersion glaucoma, and hyphema.³⁰
  
• Compared with scleral fixation of IOLs, CMS fixation is simpler and easier to perform. When the IOL haptics are sutured to the capsule, complications such as decentration and tilt (assuming a stable and centered capsular bag), suture erosion through the sclera, and the risk of intraocular hemorrhage are all minimized.^31–34 Fixating the lens to the capsule also reduces the possible adverse effects of a simple sulcus-placed lens such as iris chafing causing iris transillumination defects, uveitis-glaucoma-hyphema syndrome, or sunset syndrome.^24,25 Most importantly, the sutures are safer and simpler to perform because they are entirely intraocular and they are placed in avascular tissue. This reduces the possibility of infection, erosion, or granuloma formation compared with a scleral- or iris-fixated lens.
  
• The importance of adequate zonular support cannot be overemphasized because CMS fixation relies on an intact zonular apparatus. The presence of phacodonesis, iridodonesis, or IOL tilt must be carefully noted preoperatively. If capsular/zonular support is compromised, the surgeon must be prepared to consider other options, including IOL exchange with an anterior chamber, iris-sutured, or scleral-sutured IOL. Similarly, the possibility of intraoperative cheese-wiring of the capsule may persuade the surgeon to abandon CMS fixation in favor of other IOL fixation techniques. Further studies that evaluate long-term outcomes of this technique should be conducted. These issues should be addressed preoperatively with the patient as part of the informed consent process.

Decentration and subluxation of an in-the-bag or part-in- and part-out-of-the-bag PCIOL is usually a late complication, occurring years after cataract surgery. The causes include trauma, a poorly constructed anterior CCC, asymmetric intraoperative haptic placement, pseudoexfoliation syndrome, connective tissue diseases, high myopia, progressive zonular dehiscence, and previous vitrectomy.35

The same concept of using the fibrotic anterior CCC rim for suture fixation of 3-piece IOL haptics to the fibrotic elements of capsular membranes is used to center and fixate the bag-IOL complex.^18,27,36 Suturing the fibrotic CCC directly to the sclera using a modification of the Hoffman¹³ and Chan¹⁵ techniques was described by Gimbel et al in 2011.³⁶

SURGICAL TECHNIQUE

1. Preparation and draping are performed in the usual sterile manner, and local anesthesia drops are instilled. The white-to-white corneal diameter is measured with calipers. For required fixation at 12:00, 2 limbal paracenteses are made at 2:30 and 9:30 using a 2.0-mm diamond blade.
   
2. A limited superior conjunctival peritomy is done. Then a 3.0-mm half-thickness scleral-tunnel pocket incision is made, starting 1.0 mm posterior to the limbus for a modified Hoffman technique.¹³
   
3. To fixate the bag-IOL complex, 2 curved needles of a double-armed 9-0 polypropylene suture (D8229; Ethicon) are required. The first is passed through the 9:30 paracentesis and pupil, through the fibrotic CCC rim, behind the iris, and through the superior scleral pocket incision. The other needle of the double-armed suture is then passed in a similar fashion, but this time over the fibrotic CCC. The ends are partly tied until IOL centration is confirmed.
   
4. Once the IOL is deemed well-centered and stable, the knots are completed, the superior scleral flap is closed with a single interrupted 10-0 nylon suture, and the overlying conjunctiva is closed with 2 wing 10-0 polyglactin (Vicryl; Ethicon) sutures. Topical antibiotic/steroid drops are instilled. Steps are seen in Video 25-2.

IMPORTANT POINTS

• Vitrectomy is not routinely performed with the repositioning procedure, but when required, a limbal or pars plana approach may be used. A small bolus of preservative-free or rinsed triamcinolone acetonide helps to better visualize the vitreous. If the zonules are almost gone, the IOL may be stabilized before anterior vitrectomy using a single-armed 10-0 polypropylene (Prolene) suture on a curved needle. The suture is passed from the 9:30 paracentesis through the pupil and capsular membrane and out through the 2:30 paracentesis using a 26-gauge needle to guide it, as initially described by Chan et al.¹⁵ This stabilizing suture will be removed when the bag-IOL suturing is complete.
  
• To provide greater fixation and better centration of the IOL, a modification of this technique, using 2 points—and at times 3 or 4 points—rather than 1 point may be needed in some situations. This would offer more stability of the IOL, as forces are more evenly distributed and sideways displacement, which may occur with 1-point fixation, is prevented.
  
• It is important that suture knots are not permanently tied until the bag-IOL complex is accurately centered, at which point all knots may be tied.

Suture Refixation and Recentration of Cionni CTR-IOL-Bag Complex

The Cionni capsular tension ring (CTR) is a device designed by Cionni and Osher³⁷ to enable stabilization and centration of an IOL-capsular bag complex in the presence of extensive zonular dehiscence and to prevent late decentration of the IOL in cases with progressive zonulopathy. The CTR has 1 or 2 fixation hooks with eyelets that permit suture fixation of the CTR to the sclera. However, rupture of the scleral suture is a known complication that can lead to late decentration of the CTR-IOL-capsular bag complex.^38,39 If decentration occurs, one option is removal of the CTR-IOL-capsular bag complex with implantation of an anterior chamber, iris-fixated, or scleral-fixated IOL. However, these procedures can be associated with increased surgical trauma, requirement of a large incision leading to increased postoperative astigmatism, and suture- and IOL-related complications. The subluxated Cionni CTR complex may be refixated to the sclera using the Cionni CTR eyelet and adding extra CCC-scleral sutures, where needed, through the fibrotic CCC to center the IOL perfectly. This technique was described by Gimbel and Amritanand in 2013.40 It is an extension of the previously described technique of fixation of the IOL-capsular bag complex.

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