In the 2015 American Society of Retina Specialists’ Preferences and Trends Survey, 84.2% of US vitreoretinal specialists reported that the preferred treatment strategy for a dislocated intraocular lens (IOL) would be combined pars plana vitrectomy (PPV) and IOL implantation as a single procedure.¹ In addition to “tried and true” anterior chamber IOL placement, several surgical strategies have been described in recent years for the management of aphakia with poor capsular support.^2-10 Utilizing sutured and sutureless strategies, these newer techniques take advantage of smaller-gauge instrumentation, versatile suture material, small clear corneal incisions, and foldable IOLs.

RECENT TECHNIQUES

Common vitreoretinal surgery options for IOL implantation include open-loop anterior chamber IOL (ACIOL) placement, scleral-sutured posterior-chamber IOL (PCIOL) placement, and sutureless scleral fixation of a PCIOL. Although iris-based fixation of a PCIOL can be effectively employed,¹¹ iris fixation is not as commonly utilized in conjunction with vitreoretinal surgery in the United States. While the general technique for ACIOL remains similar to what has been used in the past (scleral tunnel incision, use of a Sheets glide, and so on), several options for sutured or sutureless scleral fixation have been described since 2012.

Gore-Tex Sutured PCIOL

First described in 2014 at Wills Eye Hospital,³ combined PPV and scleral fixation of a PCIOL using Gore-Tex (W. L. Gore & Associates) has been subsequently studied, with both short-term and long-term outcomes reported. Gore-Tex suture is a nonabsorbable, polytetrafluoroethylene monofilament suture with greater tensile strength than polypropylene (Prolene; Ethicon) and thus a theoretically reduced risk of suture erosion or breakage.

Described in detail elsewhere,^3,8,12 the technique involves creation of 4 separate sclerotomy sites (2 nasal and 2 temporal) created 180° apart (Figure 1). The sclerotomy sites are placed 2.5 mm to 3 mm posterior to the limbus and 4 mm to 5 mm apart and can be constructed using 23-gauge, 25-gauge, or 27-gauge trocars. After lacing a PCIOL using the Gore-Tex suture (most commonly, a Bausch + Lomb Akreos AO60 or enVista MX60 IOL), each end of the Gore-Tex suture is passed into the anterior chamber and pulled out of each corresponding sclerotomy using intraocular forceps in a hand-to-hand technique.

The foldable IOL can then be placed into the posterior chamber via a clear corneal incision (most common) or a scleral tunnel incision (typically when a rigid IOL must be explanted), and the suture ends are tied on the sclera to center the IOL. The suture knots are buried to prevent conjunctival erosion. The technique can be performed either with conjunctival peritomies or via a transconjunctival approach. An illustrative video accompanies this article and demonstrates the key steps of the procedure (watch the video at www.retinalphysician.com ).

Video 1. Combined pars plana vitrectomy, removal of a dislocated rigid IOL, and scleral fixation of an EnVista MX60 intraocular lens (Bausch + Lomb) using Gore-Tex suture (W. L. Gore & Associates).
Video courtesy Ferhina Ali, MD, and Michael Klufas, MD

Khan et al reported 1-year outcomes in 84 eyes undergoing the technique concurrently with PPV.⁸ At mean follow-up of 598±183 days (median 533 days, range 365-1,323 days), mean best available visual acuity improved from 20/782 preoperatively to 20/65 postoperatively (P<.001). The most common postoperative complications included transient vitreous hemorrhage in 6 eyes (7.1%), cystoid macular edema in 4 eyes (4.8%), and ocular hypertension in 3 eyes (3.6%). There were no cases of postoperative endophthalmitis, suture erosion/breakage, IOL dislocation, retinal detachment, or persistent postoperative inflammation during the follow-up period.

Importantly, delayed postoperative complications (after 90 days postoperatively) were not observed; when present, postoperative complications were diagnosed within 10 days of surgery and were managed medically without additional surgical intervention.

Sutureless Scleral Fixation of a PCIOL

The core method of sutureless scleral fixation involves creation of 2 scleral tunnel incisions, positioned in the ciliary sulcus 180° apart, that are used to fixate haptics of a 3-piece IOL. While several variations exist, the published techniques largely vary in regard to the method of creating the scleral tunnel incisions.

MVR blade technique

In the microvitreoretinal (MVR) blade technique, first described in 2012 by Prenner and colleagues,² limited nasal and temporal conjunctival peritomies are created, and a 20-gauge MVR blade is used to create 2 sclerotomies located 2 mm posterior to the limbus and positioned 180° apart. Using a 23-gauge trocar, two 3-mm scleral tunnels are then fashioned that terminate into the respective sclerotomy site. Each haptic of a 3-piece IOL is then externalized via the sclerotomy site and placed into the scleral tunnel using intraocular forceps. Of note, the 20-gauge sclerotomy sites may be sutured for stability of the haptic until the scleral tunnels have sufficient time to scar.

Wilgucki et al reported 1-year outcomes utilizing this technique in a series of 24 eyes.⁶ At final follow-up, mean visual acuity improved from 20/399 to 20/66. The most common postoperative complications included IOL dislocation in 3 eyes (12%) and vitreous hemorrhage in 2 eyes (8%).

Trocar-cannula technique

In a modified technique described by Associated Retinal Consultants/Beaumont Hospital, sclerotomy sites and associated scleral tunnel incisions can be created in a transconjunctival approach using 23-gauge, 25-gauge, or 27-gauge trocar cannulas.⁵ Each haptic of a 3-piece IOL is then grasped using intraocular forceps (commonly Maxgrip-style serrated forceps). With the haptic still grasped by the forceps in the posterior segment, the valved cannulas are first displaced to the shaft of the intraocular forceps and the haptic can then be externalized directly into the scleral tunnel incision.

Todorich et al reported clinical outcomes of 122 eyes undergoing the technique with mean follow-up of 1.52 years (range 0.4-4.5 years).⁹ Mean visual acuity improved overall from 20/633 to 20/83 at final follow-up, with a mean final scleral equivalent of -0.57 D. The most common postoperative complication was vitreous hemorrhage in 27 eyes (22.1%), of which 8 eyes required subsequent PPV for clearance, and cystoid macular edema in 26 eyes (21.3%). A subsequent surgery due to IOL positioning or haptic issues (disinsertion, malposition, or breakage) was necessary in 13 eyes (10.7%).

Double-needle technique

Yamane et al first described a double-needle–based method for sutureless scleral fixation in 2014.⁴ Initially using a lamellar scleral dissection and 27-gauge needles, the technique has been modified to a fully transconjunctival approach using 30-gauge needles and without need for scleral dissection.⁷

Briefly, two 30-gauge thin-walled needles (TSK needles; Tochigi Seiko) are utilized to create 2 angled scleral tunnel incisions/tracts 2 mm from the limbus positioned 180° apart. The leading and trailing haptic of a 3-piece IOL are then threaded into the respective needle lumens using intraocular forceps. Once secure, the 2 needles are then externalized to leave the haptics housed within the scleral tract (Figure 2).

Yamane et al reported outcomes in 97 eyes undergoing the double-needle technique with mean follow-up of 20.6 ±10.0 months (range 6.0-42.9 months).⁷ IOL tilt measurements were performed, with a mean final IOL tilt of 3.4°±2.5°. The mean refractive difference from the predicted in-the-bag calculation (by the Sanders-Retzlaff-Kraff trial formula) was 0.21±0.99 D across the four IOL options utilized in the study. Postoperative complications included iris capture by the IOL in 8 eyes (8%) and vitreous hemorrhage in 5 eyes (5%); no cases of haptic breakage or endophthalmitis were reported.

“Flanged” IOL fixation

To reduce the risk of haptic slippage or dislocation during sutureless scleral fixation techniques, several authors have described methods to improve haptic stability within the scleral tunnel incisions. Yamane et al first coined the term “flanged IOL fixation.”7 At the conclusion of double-needle–based sutureless fixation, the ends of externalized haptics are heated into a bulb, or “flange,” using low-temperature cautery (Figure 3). The flanged haptics are then reposited into the needle tract housing the body of the haptic, with the bulk of the flanged haptic end helping to prevent slippage out of the needle tract. In their series of 97 eyes using double-needle fixation and flanged haptic technique, no cases of IOL dislocation were noted in the follow-up period.⁷

Walsh et al subsequently adopted flanging of haptics following sutureless scleral fixation using the trocar-cannula–based technique.¹⁰ Reporting on outcomes of 11 eyes, no cases of IOL dislocation, subluxation, or haptic extrusion were noted with minimum follow-up of 3 months.

COMPARATIVE OUTCOMES

Despite the recent description of several surgical techniques, few reports directly compare clinical outcomes between IOL implantation options. Abbey et al respectively compared outcomes of the MVR blade (8 eyes) vs trocar-cannula (15 eyes) sutureless scleral fixation techniques at a mean follow-up of 353 days (range 94-790 days).⁵ Overall mean visual acuity improved from 20/297 to 20/47, with significant improvement noted for both the MVR blade (P=.03) and trocar-cannula (P<.001) techniques. No cases of postoperative IOL dislocation or haptic erosion were encountered with either method. However, haptic dislocation during surgery (3 vs 0 eyes), cystoid macular edema (2 vs 0 eyes), and hypotony (2 vs 0 eyes) were noted more often with the trocar-cannula method as compared with the MVR blade method. While patient numbers were small and the study was performed prior the advent of other modifications, such as flanged haptics, the study supported the effective use of both sutureless scleral fixation techniques.

Recently, Khan et al retrospectively compared clinical outcomes of combined vitrectomy with ACIOL vs scleral fixation of a PCIOL using Gore-Tex suture for retained lens material, aphakia, or dislocated IOL indications.¹³

To remove confounding of concurrent pathology, eyes with a history of significant retinal or concurrent vision-limiting ocular disease were excluded from the analysis. At mean follow-up of 502±165 days (median 450, range 365-1,095 days), mean best available visual acuity was 20/50 in eyes undergoing ACIOL implantation (n=33 eyes) vs 20/46 in eyes with a scleral-fixated PCIOL (30 eyes, P=.62). While the rate of intraoperative and postoperative complications was low, eyes undergoing ACIOL placement had a higher rate of transient corneal edema (30.3% vs 6.7%, P=.02) in the early postoperative period compared with eyes undergoing scleral fixation of a PCIOL. Similar to the findings of Wagoner et al,¹¹ both the ACIOL and Gore-Tex sutured PCIOL technique improved vision and were well tolerated, with no differences at 1 year in regard to adverse events.

PREOPERATIVE CONSIDERATIONS

The choice of surgical technique depends on many factors, including comorbid ocular conditions, iris and capsule anatomy, and surgeon preference. When considering the choice of technique, the following factors are worthy of consideration.

Surgical Plan: IOL Exchange, Rescue, or Secondary Placement?

If encountering a dislocated 3-piece IOL, the IOL may be rescued if utilizing a sutureless intrascleral fixation technique. The vitreous cutter can be used to remove any capsular bag or Soemmering ring remnants prior to fixation, but care should be taken to ensure there is no haptic damage prior to intrascleral fixation. Moreover, if intraoperative complications arise during IOL-related surgery, it may be best to complete vitrectomy and IOL removal and opt for secondary IOL implantation at a later time.

Age and Ocular Anatomy

Particularly following trauma, iris anatomy may preclude placement of an ACIOL or an iris-fixated PCIOL. Similarly, while largely associated with older, closed-loop designs, concerns regarding corneal decompensation and glaucoma following ACIOL implantation may make PCIOL placement the preferred option in younger patients.

Moreover, in eyes with significant conjunctival loss, scarring, a glaucoma-related filtering bleb, or concurrent hardware (eg, tube shunt plate), the conjunctiva should be carefully examined preoperatively to plan placement of sclerotomy sites or scleral tunnel incisions necessary for scleral fixation. Particularly in techniques where a peritomy may be required, adequate conjunctival closure over scleral sutures or externalized haptics is necessary to prevent erosion or exposure to help minimize endophthalmitis risk.

IOL Choice

Several IOL choices can be utilized. For the Gore-Tex sutured PCIOL technique, the foldable Bausch + Lomb Akreos AO60 or EnVista MX60 IOL are now most commonly used. An Alcon CZ70BD IOL may also be used, but this requires a large scleral tunnel incision for implantation. As has been reported with hydrophilic acrylic IOLs such as the Akreos AO60, optic opacification may occur following exposure to intraocular air or gas.¹⁴ As such, cases in which posterior segment tamponade is necessary, use of the EnVista MX60 is advised to avoid this risk.

For sutureless intrascleral fixation, the Alcon MA50BM, Alcon MA60AC, and Aaren Scientific EC-3 PAL are commonly used IOLs. Due to the larger optic size of the MA50BM and more pliable haptics of the EC-3 PAL, these IOLs may be more forgiving particularly when first completing cases.

Lastly, planned wound construction may be a consideration when choosing an IOL. For instance, if a rigid, one-piece PMMA IOL has dislocated, a large scleral tunnel incision would be necessary for removal. In this setting, an ACIOL can easily be implanted via the same scleral tunnel incision.

Be Prepared: Reverse Pupillary Block

Reverse pupillary block has been observed following both sutured and sutureless scleral fixation of a PCIOL.^15,16 If present postoperatively, creation of a laser peripheral iridotomy is indicated.

Surgical Learning Curve

As with any new technique, a surgical learning curve should be anticipated. The changing complication rate profiles when comparing early and later reports of the above-described techniques are proof of this phenomenon.^8,12 Ordering “back-up” IOLs and allowing added surgical time may be helpful when planning early cases.

FUTURE DIRECTIONS

As techniques continue to evolve, including iris-based fixation methods such as the iris-claw IOL,¹⁷ ongoing assessment of outcomes is important for best practices. Prospective, comparative studies will ultimately be necessary to identify if a specific technique or IOL choice is preferred. Importantly, while outcomes-related reports have thus far been favorable, long-term data are lacking and results should be interpreted on a short- and intermediate-term basis.

Looking forward, attention to refractive aim and outcomes will be important to ensure anticipated visual outcomes are delivered with each respective technique and IOL choice. Similarly, attention to precise sclerotomy site and scleral tunnel placement to optimize position within the ciliary sulcus and avoid IOL tilt will be of special interest. For instance, cadaveric studies have been performed to measure stress on haptics with varying sclerotomy site positions.⁹ Data from future studies may help clarify optimal tunnel and haptic positioning.

CONCLUSION

Since the 2003 ophthalmic technology assessment report by Wagoner et al, which reviewed options for IOL placement in the absence of capsular support,¹¹ several new techniques for sutured and sutureless scleral fixation of a PCIOL have been described that take advantage of the skill set and instrumentation of the vitreoretinal surgeon. Outcomes reports have been favorable, supporting the effective use of each technique in the proper clinical setting. Moreover, the ongoing refinement and modification of these techniques reflect the desire of the vitreoretinal community to continue to improve the ease of use and efficacy of IOL implantation in the setting of poor capsular support. Careful preoperative assessment and surgical technique can lead to excellent visual outcomes with low rates of intraoperative and postoperative complications. RP

REFERENCES

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