Spontaneous late dislocation of intraocular lens within the capsular bag in pseudoexfoliation patients

Spontaneous Late Dislocation of Intraocular Lens Within the Capsular Bag in Pseudoexfoliation Patients Faisal S. Jehan, MD, Nick Mamalis, MD, Alan S. Crandall, MD Purpose: To identify a delayed complication of cataract surgery in patients with zonular weakness caused by pseudoexfoliation syndrome. Design: Retrospective observational case series. Participants: Eight eyes in seven patients with clinically diagnosed pseudoexfoliation syndrome who had undergone previous uncomplicated cataract extraction and placement of a posterior chamber intraocular lens. Methods: This study evaluated eight cases of late spontaneous dislocation of posterior chamber intraocular lenses within the capsular bag in patients with pseudoexfoliation syndrome. Data were gathered retrospectively from patients’ operative reports, medical records, and pathology reports. Main Outcome Measures: (1) Interval between original surgery and dislocation; (2) final best-corrected visual acuity and ocular outcome. Results: All patients had a diagnosis of pseudoexfoliation syndrome and had previously undergone uncomplicated cataract surgery. No patient had any other predisposing factors that would lead to zonular dehiscence or weakness. Delayed dislocation of the entire capsular bag containing the intraocular lens (IOL) occurred spontaneously in all cases. Mean time from IOL implantation to dislocation was approximately 85 months (7 years and 1 month; range, 57–115 months) after surgery. Seven eyes were treated successfully with IOL exchange: six with placement of an anterior chamber IOL and one with scleral fixation of a posterior chamber IOL. The remaining case was treated by scleral fixation of the dislocated IOL. Gross pathology analysis of seven cases confirmed the presence of the IOL within the intact capsular bag. Six eyes have achieved final best-corrected visual acuity of 20/40 or better. Conclusion: Patients with pseudoexfoliation syndrome may be at risk for delayed spontaneous dislocation of IOL within the capsular bag after uncomplicated cataract surgery. Awareness of this newly recognized long-term complication may justify a reevaluation of surgical considerations for cataract removal in these patients. Ophthalmology 2001;108:1727–1731 © 2001 by the American Academy of Ophthalmology. Pseudoexfoliation syndrome (PEX) is a systemic disorder with ocular involvement characterized by an acellular fibrillary substance that deposits on structures that line the aqueous-bathed surfaces of the eye. PEX is clinically relevant to all anterior chamber structures and can lead to a variety of secondary complications involving the lens, zonular apparatus, ciliary body, iris, trabecular meshwork, and cornea.1 A variety of intraoperative complications during cataract surgery also occur more frequently in eyes with PEX.2– 6 Lens dislocation is a well-known complication in paOriginally received: October 24, 2000. Accepted: April 23, 2001. Manuscript no. 200578. From the Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah Health Sciences Center, Salt Lake City, Utah. Presented in part at the annual meeting of the American Academy of Ophthalmology, Dallas, Texas, October 2000. Supported in part by a grant from Research to Prevent Blindness, New York, New York, to the Department of Ophthalmology and Visual Sciences, The University of Utah. Reprint requests to Nick Mamalis, MD, 50 North Medical Drive, Salt Lake City, Utah 84132. © 2001 by the American Academy of Ophthalmology Published by Elsevier Science Inc.

tients with pseudoexfoliation. The accumulation of pseudoexfoliative material contributes to friability and decreased tensile strength of the zonular fibers7,8; this has been shown to involve proteolytic mechanisms within aggregates of pseudoexfoliative material. Dislocation may occur spontaneously or intraoperatively during cataract surgery.4 – 8 Cases of immediate postoperative dislocation2 and late decentration1 of intraocular lenses (IOLs) placed within the capsular bag have also been reported. In addition, retrospective analysis of postmortem eyes with PEX shows more pronounced decentration of IOLs compared with normal eyes. This finding is attributed to decentration of the entire capsular bag as a result of zonular weakness and damage.9 Delayed dislocation of an IOL and capsular bag has been previously reported in association with other conditions. In one of these cases, the dislocation was attributed to ocular trauma and occurred 18 months after surgery.10 Two other cases of late dislocation occurring spontaneously have been reported.11,12 These were attributed to excessive centripetal force on the zonular apparatus after a strong capsule contraction syndrome. To our knowledge there have been no previous reports of delayed spontaneous dislocation of an ISSN 0161-6420/01/$–see front matter PII S0161-6420(01)00710-2

1727

Ophthalmology Volume 108, Number 10, October 2001 IOL and of the capsular bag in patients with PEX. The purpose of this article is to report this newly recognized surgical complication and to shed further light on the clinical and surgical implications of PEX.

achieved only hand-motion vision. This patient also has macular degeneration, glaucoma, and geographic atrophy in both eyes and has had recurrent retinal detachments in the right eye.

Discussion Material and Methods Eight cases were retrospectively reviewed. Patients were identified by searching ophthalmic pathology logbooks, pathology reports, and medical records. Inclusion criteria for this study included (1) clinically diagnosed PEX, (2) a history of uncomplicated cataract extraction and implantation of a posterior chamber IOL, and (3) delayed spontaneous dislocation of the entire capsular bag containing the intraocular lens, confirmed either clinically or by gross pathologic analysis. Patients with a history of trauma, complicated surgery, or other ocular diseases that may contribute to zonular instability or IOL dislocation were excluded. Data were gathered by retrospective review of patient medical records. One patient’s medical records for the initial surgery were unavailable; this patient was interviewed by telephone to determine the approximate date of initial cataract surgery.

Results Table 1 summarizes the clinical characteristics of each case. A total of eight cases (seven patients) were reviewed. The original surgeries were performed at five different surgical centers by five different ophthalmologists in the Salt Lake City area. The original surgeries took place over a 44.5-month period from July 11, 1988, to March 30, 1992. Four of the patients were female and three were male. Cases 1 and 2 involved the right and left eye of the same patient. The patients’ median age at the time of surgery was 74 years, with a range of 55 to 76. All original surgeries performed were uncomplicated extracapsular cataract extractions using phacoemulsification with placement of a posterior chamber IOL within the capsular bag. The patients’ other ocular history included retinal detachment in two cases, glaucoma in five cases, and posterior capsular opacification of the implanted IOL requiring neodymium:yttrium–aluminum– garnet posterior capsulotomy in five cases. The mean interval from the time of original surgery to IOL dislocation was approximately 85 months (7 years, 1 month; range, 57–115 months). Original records for case 5 were unavailable; this patient was interviewed by telephone and reported that her original surgery took place in approximately January of 1990. Treatment consisted of IOL exchange with placement of an anterior chamber IOL for six patients. Three of these patients also underwent anterior vitrectomy, and one underwent pars plana vitrectomy. The remaining two cases occurred in the same patient approximately 20 months apart (Fig 1); the right eye was treated by IOL exchange, with placement of a sewn-in posterior chamber IOL in the left eye with scleral fixation of the dislocated IOL. The seven explanted IOLs were submitted for gross pathologic examination and all were found to include an intact IOL within the entire capsular bag (Fig 2). Five were found to be one-piece polymethyl methacrylate (PMMA) posterior chamber IOLs, one a three-piece PMMA IOL with polypropylene haptics, and one a plate-type silicone lens. The single case that was treated by scleral fixation of the dislocated lens involved a single-piece PMMA IOL. Final outcomes after surgical intervention for these cases varied; however, six cases achieved a best-corrected visual acuity of 20/40 or better, with two patients achieving a final best-corrected visual acuity of 20/20. Two eyes, unfortunately in the same patient,

1728

PEX is a relatively common disorder, affecting 4% to 6% of patients older than 60 years and as much as 8% to 35% after the age of 70.7 A higher incidence is found in some ethnic groups such as northern Scandinavians, Saudi Arabians, and Navajo Indians. The classic diagnostic sign is a characteristic bulls-eye appearance of the anterior lens surface, produced by pupillary wiping of a ring of pseudoexfoliative material from the lens surface. Occasionally, white flakes on the pupillary border of the iris may be the only subtle sign present. The exact cause of this condition remains unknown. Pseudoexfoliative material seems to be produced by lens epithelial cells and by cells of the iris and ciliary epithelium. This fibrillary material accumulates on the surface of structures that line the aqueous-bathed cavities of the eye, including zonular fibers, iris, ciliary body, trabecular meshwork, and the corneal endothelium. PEX is associated with numerous ocular complications, including glaucoma, lens dislocation, blood–aqueous breakdown, pigment dispersion, iris complications, and corneal endothelial decompensation.1,7 The high incidence of cataract and PEX coexisting in the same patient presents difficult challenges for the surgeon. Intraoperative and postoperative complications, including zonular disruption, crystalline lens and IOL dislocation, vitreous loss, increased intraocular pressure, and trauma to other ocular structures, occur more frequently in eyes with PEX than in eyes that do not have PEX.2– 6 Careful preoperative evaluation for the presence of PEX and increased awareness of potential intraoperative difficulties are thus important considerations in avoiding surgical complications. Lens dislocation in patients with PEX is a well-recognized condition. The lens can be dislocated spontaneously or intraoperatively.3,4,13 Contributory factors include increased friability and decreased tensile strength of the zonules, leading to their disruption and subsequent lens dislocation. Pseudoexfoliative material has been shown to disrupt the zonules at three levels: (1) at the origin of the ciliary body where they are anchored, (2) in the pars plicata of the ciliary body where they pass alongside the ciliary processes, and (3) at their attachment to the anterior lens capsule. Immunohistochemical demonstration of lysosomal enzymes within pseudoexfoliation aggregates indicate that proteolytic mechanisms facilitate this zonular disintegration.8 Various surgical techniques may be used in cases of zonular weakness or disruption. In eyes with PEX and no signs of phacodonesis or zonular rupture, phacoemulsification with placement of a posterior chamber IOL in the capsular bag should be performed with extreme care or by an experienced surgeon.1,5,14 In cases of preoperative or intraoperative zonular rupture, capsular tension rings made of PMMA may be placed within the capsular bag to facil-

Jehan et al 䡠 Delayed Spontaneous IOL Dislocation in Pseudoexfoliation Patients Table 1. Clinical Characteristics Case # Age (yrs) Gender

Original Surgery

Date of Dislocation/ Intervention

Clinical Presentation/ Intraocular Lens Type

1 76 M

Phaco/IOL implantation OD 7/11/88

1/31/95 Exchanged with sewn-in PC IOL

Inferiorly dislocated IOL One-piece PMMA

2 76 M

Phaco/IOL implantation OD 11/30/88

9/30/96 Scleral fixation of IOL

Inferiorly dislocated IOL One-piece PMMA

3 55 M

Phaco/IOL implantation OS 12/6/89

IOL dislocation into vitreous Three-piece PMMA

4 76 M

Phaco/IOL implantation OD 11/7/90

8/26/98 Pars plana vitrectomy, exchanged with AC IOL 2/28/00 Exchanged with AC IOL

5 69 F

Other Ocular History

Interval Between Original Surgery and Dislocation

Glaucoma OU 78.7 mos RD OD ’86, ’88 YAG OD ’89, ’94 Geographic atrophy Macular degeneration Glaucoma OU 94.0 mos RD OD ’86, ’88 YAG OD ’89, ’94 Geographic atrophy Macular degeneration YAG OS ’92 115.3 mos Glaucoma OU

Final Outcome after Secondary Intervention Hand-motion vision 4 yrs postoperative Hand-motion vision 27 mos postoperative BCVA 20/40 2 mos postoperative; pupillary block

PCO with inferiorly dislocated IOL One-piece PMMA

None

111.7 mos

Phaco/IOL 11/12/96 implantation Anterior vitrectomy, OS exchanged with AC Approximately early IOL 1990*

Entire zonular dehiscence with inferiorly dislocated IOL Plate-type silicone

None

72 mos BCVA 20/25 approximately 4 wks postoperative

6 78 F

Phaco/IOL implantation OS 5/22/91

2/20/96 Anterior vitrectomy, exchanged with AC IOL

Zonular dehiscence with inferior displacement of IOL One-piece PMMA

YAG OS for PCO ’95

56.9 mos

BCVA 20/30 3 yrs postoperative

7 73 F

Phaco/IOL implantation OD 6/11/91

8/26/97 Anterior vitrectomy, exchanged with AC IOL

IOL within capsular bag Glaucoma OU dislocated inferiorly into vitreous One-piece PMMA

74.5 mos

BCVA 20/40 2 yrs postoperative

8 62 F

Phaco/IOL implantation OD 3/30/92

8/26/99 Exchanged with AC IOL

Phacodonesis of IOL One-piece PMMA

79.1 mos

BCVA 20/20 6 mos postoperative; pupillary block

Glaucoma OU YAG OD ’92 and ’94

BCVA 20/20 2 wks postoperative

*Original report unavailable; data provided by patient. AC ⫽ anterior chamber; BCVA ⫽ best corrected visual acuity; F ⫽ female; IOL ⫽ intraocular lens, M ⫽ male; PC ⫽ posterior chamber; PCO ⫽ posterior capsular opacification; Phaco ⫽ phacoemulsification; PMMA ⫽ poly(methyl)methacrylate, RD ⫽ retinal detachment; YAG ⫽ Nd:YAG laser posterior capsulotomy; OD ⫽ right eye; OS ⫽ left eye; OU ⫽ both eyes.

itate safe phacoemulsification and implantation of a posterior chamber IOL. These capsular tension rings are thought to function by providing support and circular contour to the capsular bag and by evenly distributing forces on remaining intact zonules.14 –16 In cases of more pronounced zonular disruption or complete lens dislocation, IOLs may be placed in the ciliary sulcus, fixated transsclerally, or placed in the anterior chamber.1,4,5,14,15,17 Although the incidence of late spontaneous dislocation of an IOL and capsular bag in eyes with PEX is unknown, we believe these eight cases represent a significant number and justify a reevaluation of current surgical practices in cases of uncomplicated surgery. Because decentration of the entire capsular bag has been shown in postmortem eyes with

PEX, alternative fixation sites for IOLs other than within the capsular bag have been previously considered.9 Of particular relevance at the time of cataract surgery are possible alternative fixation sites that would avoid or prevent the eventual complete dislocation of the IOL and capsular bag, as seen with these patients. Modern anterior chamber IOLs may be less prone to complications such as secondary glaucoma and corneal decompensation compared with older anterior chamber IOL models.5 Placement of an anterior chamber IOL would circumvent the possibility of an IOL and capsular bag dislocation; however, these lenses are not recommended for routine uncomplicated cataract surgery in these patients because of the high incidence of glaucoma seen with PEX.3,4,16

1729

Ophthalmology Volume 108, Number 10, October 2001

Figure 1. Case 2, Clinical photograph of a patient with an inferiorly decentered one-piece polymethyl methacrylate posterior chamber intraocular lens within the capsular bag with complete loss of superior zonular support (arrow).

Ciliary sulcus placement of a posterior chamber IOL is another potential method of avoiding this delayed complication. Because of the high frequency of intraoperative complications with in-the-bag placement, the routine use of sulcus-placed IOLs in eyes with PEX has been previously advocated.17 Long-term visual outcomes with foldable IOLs placed in the ciliary sulcus have been shown to be comparable to in-the-bag placement; however, pupillary capture and increased inflammation caused by iris touch are significantly greater in sulcus fixated IOLs.18,19 Sclerally fixated posterior chamber IOLs may be another potential alternative and have been shown in retrospective studies to provide acceptable visual outcomes and low complication rates.20,21 However, this method significantly increases surgery time, and axial tilt of the IOL may occur postoperatively.16 In addition, long-term data for this method are currently unavailable. An alternative that retains advantages of in-the-bag placement that could potentially reduce the risk of delayed

Figure 2. Gross photograph of a one-piece polymethyl methacrylate posterior chamber intraocular lens completely surrounded by an intact capsular bag with a small amount of iris pigment on the anterior surface.

1730

dislocation of the IOL and capsular bag in eyes with PEX is placement of a capsular tension ring. Because these rings are thought to evenly distribute forces on intact zonules,14 –16 they theoretically could prevent progressive focal disruption of weakened zonules during moments of zonular stress. Although no randomized studies are available on the long-term performance of capsular tension rings, adequate IOL centration has been observed 2 to 11 months postoperatively in cases complicated by zonular dialysis.16 For extensive zonular dialysis, a modified capsular tension ring sutured to the sclera has also been shown to maintain adequate centration and excellent support of IOLs within the capsular bag for 2 to 8 months postoperatively.15 We suspect that the delayed nature of capsular bag and IOL dislocation reflects a multifactorial process. Contraction of the anterior lens capsule occurs in all postoperative eyes but is more pronounced in eyes with PEX.22,23 This shrinking of the anterior capsule occurs up to 3 months postoperatively and may contribute to early zonular traction and further weakening of the zonules. In addition, progressive weakening of zonular fibers inherent in PEX, combined with repeated stresses over the course of many years, may contribute to zonular dehiscence and eventual dislocation of the entire capsular bag. It is unclear whether IOL type represents a significant risk factor for late dislocation. Seven cases involved PMMA IOLs and one involved a silicone-plate IOL; however, we believe this difference likely reflects the more frequent general use of PMMA lenses by surgeons during the time of the original surgeries. The significance of posterior capsular opacification developing before dislocation in these cases is also unclear. Posterior capsular opacification occurs more frequently in eyes with PEX than in eyes without PEX24; in our series, five eyes had posterior capsular opacification develop, requiring neodymium:yttrium–aluminum– garnet laser posterior capsulotomy. It is possible that lens epithelial cell proliferation increases the IOL/capsular bag mass and may contribute to increased zonular stress by a simple mass effect. If such is the case, the use of capsular tension rings may be further supported, because they have been shown to decrease posterior capsular opacification rates in a rabbit model by a presumed mechanism of compression inhibition.25 In conclusion, patients with PEX are not only at increased risk of secondary ocular complications but also have a higher incidence of intraoperative and postoperative complications with cataract surgery. To our knowledge, these are the first reported cases of delayed spontaneous dislocation of an IOL and capsular bag in patients with PEX. An increased awareness of this potential problem and increased vigilance in long-term follow-up is recommended. Alternatives to routine placement of posterior chamber IOLs within the capsular bag during uncomplicated surgery in eyes with PEX should be considered. However, many of these surgical considerations will remain unanswered until a long-term prospective, randomized trial of various IOL fixation methods in eyes with PEX is undertaken.

Jehan et al 䡠 Delayed Spontaneous IOL Dislocation in Pseudoexfoliation Patients

References 14. 1. Naumann GOH, Schlotzer-Schrehardt U, Kuchle M. Pseudoexfoliation syndrome for the comprehensive ophthalmologist. Intraocular and systemic manifestations [review]. Ophthalmology 1998;105:951– 68. 2. Raitta C, Setala K. Intraocular lens implantation in exfoliation syndrome and capsular glaucoma. Acta Ophthalmol (Copenh)1986;64:130 –3. 3. Kirkpatrick JNP, Harrad RA. Complicated extracapsular cataract surgery in pseudoexfoliation syndrome; a case report. Br J Ophthalmol 1992;76:692–3. 4. Skuta GL, Parrish RK 2nd, Hodapp E, et al. Zonular dialysis during extracapsular cataract extraction in pseudoexfoliation syndrome. Arch Ophthalmol 1987;105:632– 4. 5. Avramides S, Traianidis P, Sakkias G. Cataract surgery and lens implantation in eyes with exfoliation syndrome. J Cataract Refract Surg 1997;23:583–7. 6. Kuchle M, Viestenz A, Martus P, et al. Anterior chamber depth and complications during cataract surgery in eyes with pseudoexfoliation syndrome. Am J Ophthalmol 2000;129:281– 5. 7. Eagle RCJ Jr, Spencer WH. Lens. In: Spencer WH, ed. Ophthalmic Pathology: An Atlas and Textbook, 4th ed. Philadelphia: WB Saunders, 1996;394. 8. Schlotzer-Schrehardt U, Naumann GOH. A histopathologic study of zonular instability in pseudoexfoliation syndrome. Am J Ophthalmol 1994;118:730 – 43. 9. Auffarth GU, Tsao K, Wesendahl TA, et al. Centration and fixation of posterior chamber intraocular lenses in eyes with pseudoexfoliation syndrome. An analysis of explanted autopsy eyes. Acta Ophthalmol Scand 1996;74:463–7. 10. Zech JC, Tanniere P, Denis P, Trepsat C. Posterior chamber intraocular lens dislocation with the bag. J Cataract Refract Surg 1999;25:1168 –9. 11. Davison JA. Capsule contraction syndrome. J Cataract Refract Surg 1993;19:582–9. 12. Nishi O, Nishi K, Sakanishi K, Yamada Y. Explantation of endocapsular posterior chamber lens after spontaneous posterior dislocation. J Cataract Refract Surg 1996;22:272–5. 13. Bartholomew RS. Lens displacement associated with pseudo-

15. 16.

17. 18.

19. 20.

21. 22.

23.

24. 25.

capsular exfoliation. A report on 19 cases in the Southern Bantu. Br J Ophthalmol 1970;54:74 ––50. Fine IH, Hoffman RS. Phacoemulsification in the presence of pseudoexfoliation: challenges and options. J Cataract Refract Surg 1997;23:160 –5. Cionni RJ, Osher RH. Management of profound zonular dialysis or weakness with a new endocapsular ring designed for scleral fixation. J Cataract Refract Surg 1998;24:1299 –306. Gimbel HV, Sun R, Heston JP. Management of zonular dialysis in phacoemulsification and IOL implantation using the capsular tension ring. Ophthalmic Surg Lasers 1997;28:273– 81. Tarkkanen AHA. Exfoliation syndrome. Trans Ophthalmol Soc UK 1986;105(Pt 2):233–5. Pandey SK, Ram J, Werner L, et al. Visual results and postoperative complications of capsular bag and ciliary sulcus fixation of posterior chamber intraocular lenses in children with traumatic cataracts. J Cataract Refract Surg 1999;25: 1576 – 84. Amino K, Yamakawa R. Long-term results of out-of-the-bag intraocular lens implantation. J Cataract Refract Surg 2000; 26:266 –70. Oshima Y, Oida H, Emi K. Transscleral fixation of acrylic intraocular lenses in the absence of capsular support through 3.5 mm self-sealing incisions. J Cataract Refract Surg 1998; 24:1223–9. Bleckmann H, Kaczmarek U. Functional results of posterior chamber lens implantation with scleral fixation. J Cataract Refract Surg 1994;20:321– 6. Hayashi K, Hayashi H, Nakao F, Hayashi F. Reduction in the area of the anterior capsule opening after polymethylmethacrylate, silicone, and soft acrylic intraocular lens implantation. Am J Ophthalmol 1997;123:441–7. Gallagher SP, Pavilack MA. Risk factors for anterior capsule contraction syndrome with polypropylene or poly(methyl methacrylate) haptics. J Cataract Refract Surg 1999;25:1356 – 61. Kuchle M, Amberg A, Martus P, et al. Pseudoexfoliation syndrome and secondary cataract. Br J Ophthalmol 1997;81: 862– 6. Hara T, Hara T, Sakanishi K, Yamada Y. Efficacy of equator rings in an experimental rabbit study. Arch Ophthalmol 1995; 113:1060 –5.

1731