Intraocular Lens Dislocation: A Vitreoretinal Perspective

BY STEPHEN G. SCHWARTZ, M.D., HARRY W. FLYNN, JR., M.D. AND WILLIAM E. SMIDDY, M.D.

Dislocation of an intraocular lens is an infrequent but serious complication of cataract surgery. Vision loss is typically sudden in onset, but it may be gradual when associated with progressive IOL malposition or cystoid macular edema (CME). Associated retinal detachment (RD) occurs in approximately 5% of patients.

IOL dislocations may be divided into in-the-bag and out-of-the-bag categories, with correspondingly different etiologies (Table 1).^1-3 The most common in-the-bag etiologies are pseudoexfoliation and prior vitreoretinal surgery.² The most common out-of-the-bag etiology is capsular rupture during cataract surgery. The dislocation may be immediately apparent or may develop months or years later. Descemet-stripping automated endothelial keratoplasty has recently been reported as a cause of out-of-the-bag IOL dislocation in one case report,⁴ although in-the-bag dislocation may also occur.

The management of a dislocated IOL depends on various factors, including the patient's ocular and general health, as well as specific considerations regarding the anatomy of the affected eye (Table 2). In patients who are poor surgical candidates and have good visual function in the fellow eye, observation of a dislocated IOL in the vitreous cavity may be a reasonable option. In this setting, contact lens correction can be considered, although aphakic spectacles may be used in monocular patients. In one such series of patients with older IOL styles (such as Copeland and Binkhorst lenses) that were observed, 60% maintained visual acuity of 20/40 or better, and 13% developed RD over an average of 3 years of follow-up (Figure 1).⁵

Figure 1. Dislocated Copeland-style intraocular lens on the retinal surface.

The majority of patients with posterior IOL dislocations are treated surgically, by either a limbal or a pars plana approach. If the IOL is still supported to some degree by the capsular remnants, an anterior-segment (limbal) approach may be considered (Figure 2). However, when the patient is supine on the operating table, the IOL frequently falls further posteriorly, making a limbal approach more difficult. Pars plana vitrectomy (PPV) techniques offer several advantages to a limbal approach, including more complete and controlled removal of formed vitreous, better access to the posterior vitreous cavity and better ability to address potential intraoperative complications, such as retinal tear, suprachoroidal hemorrhage or progressive IOL dislocation into the posterior vitreous (Figure 3).

Figure 2. Subluxed posterior chamber intraocular lens, partially supported by capsular remnants.

Figure 3. Dislocated anterior-chamber intraocular lens on the retinal surface.

Depending on the IOL type and the ocular anatomy, the dislocated IOL may be repositioned or exchanged. Patients with accommodating or multifocal IOLs may prefer to have the original IOL retained and recentered, but more precise centration is necessary for these lenses. If there is adequate capsular support, the IOL may be repositioned to the ciliary sulcus. Otherwise, the IOL may be sutured to the posterior surface of the iris or to the sclera, using one of several possible techniques, including externalization of one or both haptics.⁶

If the IOL is to be exchanged, the surgeon may choose between an anterior-chamber versus a posterior-chamber IOL (sulcus fixated, iris- or sulcus-sutured). Anterior-chamber IOLs may be associated with anterior-segment complications, such as corneal endothelial dysfunction. Sutured posterior-chamber IOLs may be associated with late-onset posterior dislocation, perhaps due to degradation of the suture material⁷ or rotation of the haptic out of the suture loop. The reported incidence of dislocation of scleral-fixated IOLs varies, but it is generally in the range of 6% or less.⁸ In one series with an average of 67 months follow-up, suture breakage and IOL dislocation occurred in 28% of eyes.⁹

Retinal detachment is an important comorbidity associated with dislocated IOLs. Up to 6% of patients with a dislocated IOL present with associated RD,¹⁰ and up to 10% of patients develop RD following PPV (Table 3).¹¹

In reported case series, visual acuity outcomes are highly variable. The percentages of eyes achieving visual acuity of 20/40 or better following PPV for dislocated IOL range between 50% to 100% (Table 3).^12-14 A multitude of techniques are used to reposition or exchange the intraocular lenses, although in general they yield comparable anatomic and visual outcomes. For example, 25-gauge instrumentation may be helpful in repositioning a dislocated IOL into the ciliary sulcus.¹⁵ In one nonrandomized series, the use of an anterior-chamber IOL was associated with more favorable visual outcomes (greater increase in mean visual acuity).¹¹

In the event of intraoperative dislocation of a posterior-chamber IOL, it is generally preferable to perform anterior vitrectomy as necessary to avoid vitreous prolapse into the anterior chamber and wound. If the IOL may be readily retrieved with a limbal approach, it may be repositioned during the same surgery. Otherwise, the wound can be closed in standard fashion, and the patient can be referred to a vitreoretinal surgeon for IOL repositioning or exchange. Frequently, PPV is delayed by 1 week or more in order to allow intraocular inflammation and corneal edema to recede. The vitreoretinal surgeon may choose IOL repositioning or exchange, based on the IOL style and specific anatomic considerations (capsular support, corneal endothelial status, etc.). When the IOL is on the retinal surface, flexible, silicone plate haptic IOLs may be difficult to grasp. The use of active suction with a vitrector to engage the IOL, or perfluorocarbon liquids to "float" the IOL anteriorly, may be helpful.

Despite advances in small-incision cataract surgery, IOL dislocation remains an important intraoperative or postoperative complication. Excellent anatomic and visual outcomes can be achieved for the majority of patients using modern PPV techniques. OM

References

1. Hayashi K, Hirata A, Hayashi H. Possible predisposing factors for in-the-bag and out-of-the-bag intraocular lens dislocation and outcomes of intraocular lens exchange surgery. Ophthalmology. 2007;114:969-75.
2. Davis D, Brubaker J, Espandar L, et al. Late in-the-bag spontaneous intraocular lens dislocation: evaluation of 86 consecutive cases. Ophthalmology. 2009;116:664-70.
3. Brilakis HS, Lustbader JM. Bilateral dislocation of in-the-bag posterior chamber intraocular lenses in a patient with intermediate uveitis. J Cataract Refract Surg. 2003;29:2013-4.
4. Tay E, Rajan MS, Saw VP, Dart JK. Dislocated intraocular lens into the vitreous cavity after DSAEK. J Cataract Refract Surg. 2008;34(3):525-6.
5. Flynn HW Jr. Management and repositioning of posteriorly dislocated intraocular lenses. In: Stark WJ (ed), Anterior Segment Surgery: IOLs, Laser and Refractive Keratoplasty, Vol 15, pp 321-9. Baltimore, MD: Williams and Wilkins, 1986.
6. Chan CK. An improved technique for management of dislocated posterior chamber implants. Ophthalmology. 1992;99:51-7.
7. Price MO, Price FW Jr, Werner L, et al. Late dislocation of scleral-sutured posterior chamber intraocular lenses. J Cataract Refract Surg. 2005;31:1320-6.
8. Bading G, Hillenkamp J, Sachs HG, Gabel VP, Framme C. Long-term safety and functional outcome of combined pars plana vitrectomy and scleralfixated sutured posterior chamber lens implantation. Am J Ophthalmol. 2007;144:371-7.
9. Vote BJ, Tranos P, Bunce C, Charteris DG, Da Cruz L. Long-term outcome of combined pars plana vitrectomy and scleral fixated sutured posterior chamber intraocular lens implantation. Am J Ophthalmol. 2006;141:308-12.
10. Campo RV, Chung KD, Oyakwa RT. Pars plana vitrectomy in the management of dislocated posterior chamber lenses. Am J Ophthalmol. 1989;108:529-33.
11. Sarrafizadeh R, Ruby AJ, Hassan TS, et al. A comparison of visual results and complications in eyes with posterior chamber intraocular lens dislocation treated with pars plana vitrectomy and lens repositioning or lens exchange. Ophthalmology. 2001;108:82-9.
12. Smiddy WE, Ibanez GV, Alfonso E, Flynn HW Jr. Surgical management of dislocated intraocular lenses. J Cataract Refract Surg. 1995;21:64-9.
13. Sternberg P Jr, Michels RG. Treatment of dislocated posterior chamber intraocular lenses. Arch Ophthalmol. 1986;104:1391-3.
14. Lawrence FC 2nd, Hubbard WA: "Lens lasso" repositioning of dislocated posterior chamber intraocular lenses. Retina. 1994;14:47-50.
15. Chang S, Coll GE. Surgical techniques for repositioning a dislocated intraocular lens, repair of iridodialysis, and secondary intraocular lens implantation using innovative 25-gauge forceps. Am J Ophthalmol. 1995;119:165-74.
16. Flynn HW Jr, Buus D, Culbertson WW. Management of subluxated and dislocated intraocular lenses using pars plana vitrectomy instrumentation. J Cataract Refract Surg. 1990;16:51-6.
17. Maguire AM, Blumenkranz MS, Ward TG, Winkelman, JZ. Scleral loop fixation for posteriorly dislocated intraocular lenses: operative technique and long-term results. Arch Ophthalmol. 1991;109:1754-8.
18. Smiddy WE, Flynn HW Jr. Management of dislocated posterior chamber intraocular lenses. Ophthalmology. 1991;98:889-94.
19. Panton RW, Sulewski ME, Parker JS, et al. Surgical management of subluxed PC-IOLs. Arch Ophthalmol. 1993;111:919-26.
20. Schneiderman TE, Johnson MW, Smiddy WE, et al. Surgical management of posteriorly dislocated silicone plate IOLs. Am J Ophthalmol. 1997;123:629-35.
21. Mittra RA, Connor TB, Han DP, et al. Removal of dislocated intraocular lenses using pars plana vitrectomy with placement of an open-loop, flexible anterior chamber lens. Ophthalmology. 1998;105:1011-4.
22. Mello M Jr, Scott IU, Smiddy WE, et al. Surgical management and outcomes of dislocated IOLs. Ophthalmology. 2000;107;162-7.
23. Gross JG, Kokame GT, Weinberg DV, et al. In-the-bag intraocular lens dislocation. Am J Ophthalmol. 2004;137:1-6.
24. Steinmetz RL, Brooks HL Jr, Newell CK. Management of posteriorly dislocated posterior chamber intraocular lenses by vitrectomy and pars plana removal. Retina. 2004;24:556-9.
25. Smiddy WE. Management of dislocated foldable intraocular lenses. Retina. 2005;25:576-80.
26. Kim SS, Smiddy WE, Feuer W et al. Management of dislocated intraocular lenses. Ophthalmology. 2008;115:1699-704.