- Email: [email protected]
Surgical Repositioning of Dislocated Capsular Tension Rings
Surgical Repositioning of Dislocated Capsular Tension Rings Iqbal Ike K. Ahmed, MD,1,2 Sylvia H. Chen, BSc,3 Christoph Kranemann, MD,1 David T. Wong, MD1 Purpose: To present techniques and results of surgical repositioning of subluxed and dislocated capsular tension rings (CTRs). Design: Retrospective interventional case series. Participants: Eleven patients with a previously implanted CTR in-the-bag for zonular weakness who presented with CTR–intraocular lens (IOL)– capsular bag decentration who underwent surgical repositioning. Methods: Data from 11 patients who underwent surgical repositioning were evaluated retrospectively for underlying diagnosis, interval between initial surgery and decentration, surgical technique, clinical results, and complications. Main Outcome Measures: Capsular tension ring–IOL– capsular bag centration, final best-corrected visual acuity (BCVA), and surgical complications. Results: Of the 11 patients with CTR decentration, 3 had it early in the postoperative period, and 8 had it late. Mean (⫾ standard deviation) durations from cataract extraction and CTR implantation to surgical repositioning were 6.1⫾7.9 months for those with decentration early and 49.6⫾15.3 months for late decentrations (overall range, 0.7–74.7). Of the 11 patients, 7 had pseudoexfoliation, and 4 of the 7 had associated glaucoma. Nine patients had subluxation of the CTR–IOL– capsular bag complex, which was managed by an anterior segment approach. A pars plana vitrectomy and levitation of the CTR was required in 2 patients due to complete dislocation of the CTR into the posterior vitreous. Surgical techniques for repositioning included single, double, or 3-point scleral suture loop fixation of the CTR through the capsular bag complex (8 eyes); use of the capsular tension segment (CTS) placed within the capsular bag for scleral suture fixation (2); or iris suture fixation of the IOL haptics (1). All patients achieved successful anatomical repositioning of the CTR–IOL– capsular bag complex. Mean preoperative BCVA improved from 20/100 to 20/40 postoperatively. After repositioning surgery, BCVA improved in 7 patients, was maintained in 2, and worsened in 2 (due to advanced glaucoma). Conclusion: Postoperative CTR subluxation or dislocation is a risk for patients with severe or progressive zonulopathy. Decentrations may be effectively managed with scleral suture fixation of the CTR through the capsular bag or the use of the CTS. Ophthalmology 2005;112:1725–1733 © 2005 by the American Academy of Ophthalmology.
The capsular tension ring (CTR), described initially by Hara et al1 and Nagamoto and Bissen-Miyajima2 and further developed by Witschel and Legler (Legler U, Witschel B. The capsular ring: a new device for complicated cataract surgery. Film presented at: American Society of Cataract and Refractive Surgery [ASCRS] Symposium on Cataract, IOL, and Refractive Surgery, May, 1993; Seattle, Washington), provides stabilization of the capsular bag and intraocular lens (IOL) during and after cataract surgery in cases of zonular instability. The circular polymethyl methacrylate
Originally received: January 2, 2005. Accepted: May 9, 2005. Manuscript no. 2005-3. 1 University of Toronto, Toronto, Canada. 2 University of Utah, Salt Lake City, Utah. 3 McGill University, Montreal, Canada. The authors have no financial interest in any of the products discussed in the article. Correspondence and reprint requests to Iqbal Ike K. Ahmed, MD, Credit Valley EyeCare, 3200 Erin Mills Parkway, Unit 1, Mississauga, Ontario, L5L 1W8, Canada. E-mail: [email protected]. © 2005 by the American Academy of Ophthalmology Published by Elsevier Inc.
open-ended filament is placed within an intact capsular bag to buttress areas of poor zonular support while recruiting and redistributing tension from existing zonules circumferentially. The CTR is placed at the time of initial surgery and is maintained at the capsular equator for postoperative centration. Early results show that, for mild generalized zonular weakness or localized zonular dialysis (i.e., ⱕ4 clock hours), the CTR provides adequate support for in-the-bag IOL centration.3–5 Although data are currently unavailable on long-term efficacy, it is felt CTR placement may prevent late-onset decentration in high-risk eyes. Indications include pseudoexfoliation syndrome; trauma; and postoperative, iatrogenic, and congenital conditions. Cataract surgeons have benefited from the use of the CTR for complex zonular cases, thus increasing its popularity. Standard CTRs do not necessarily recenter an already severely subluxed or dislocated lens in profound zonulopathy. Furthermore, many zonular conditions are progressive, and although the CTR can provide initial support, some patients may suffer late-onset CTR dislocation. This may ISSN 0161-6420/05/$–see front matter doi:10.1016/j.ophtha.2005.05.006
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Ophthalmology Volume 112, Number 10, October 2005 Table 1. Case
No.
Age (yrs) Gender
1
72 M
PXG
Phacoemulsification/trabeculectomy/IOL/CTR 60.0
Anterior vitreous
2 3 4 5 6 7
54 F 70 M 72 M 47 M 58 M 79 F
PXF PXG PXF Trauma Trauma PXG
Phacoemulsification/IOL/CTR 41.9 Phacoemulsification/IOL/CTR 37.4 Phacoemulsification/IOL/CTR 0.7 Phacoemulsification/IOL/CTR 74.7 Phacoemulsification/IOL/CTR ⫻2 24.1 Phacoemulsification/trabeculectomy/IOL/CTR 55.4
Posterior vitreous Sunset, anterior vitreous Sunset, anterior vitreous Inferotemporal Sunset, anterior vitreous Sunset, anterior vitreous
8 9
69 F 76 F
Iatrogenic PXG
Phacoemulsification/IOL/CTR 2.5 Phacoemulsification/IOL/CTR 52.3
10 11
61 F 69 M
PXF CMG
Phacoemulsification/IOL/CTR 51.0 Phacoemulsification/trabeculectomy/IOL/CTR 15.2
Nasal Marked pseudophacodinests slight sunset Posterior vitreous Marked pseudophacodinesis slight sunset
Diagnosis
Original Surgery Duration (mos)
CTR/IOL Position*
BCVA ⫽ best-corrected visual acuity; CF ⫽ counting fingers; CMG ⫽ combined mechanism glaucoma; CTR ⫽ capsular tension ring; CTS ⫽ capsular vitrectomy; PXF ⫽ pseudoexfoliation syndrome; PXG ⫽ pseudoexfoliation glaucoma. *CTR within capsular bag in all cases. † If applicable.
lead to reduced visual acuity (VA), uveitis, and cystoid macular edema.6 Dislocation of a CTR during a surgical complication and in the presence of a posterior capsular rent has been reported. Management in these cases involves removal of the displaced CTR and/or IOL.6 –9 With early case reports and, perhaps, impending problems as CTR use increases, little has been published on decentered in-the-bag CTRs due to profound zonulysis or progressive zonular weakness (Kranemann C. Late subluxation of capsular tension ring. Poster presented at: ASCRS Symposium on Cataract, IOL, and Refractive Surgery, April, 2003; San Francisco, California).10,11 Decentered inthe-bag CTRs may be categorized as those subluxed within the retropupillary space/anterior vitreous and those that have dislocated into the posterior vitreous cavity. Although CTR removal and IOL exchange is an option in these cases, our preference has been to maintain a closed-system minimally invasive approach of surgical repositioning with suture fixation. We are unaware of any published series on features, operative techniques, or results of management of CTR decentration with surgical repositioning. Here we report details and the management of subluxed or dislocated CTR–IOL– capsular bag using repositioning techniques.
Materials and Methods A retrospective chart review of 11 patients who underwent surgical repositioning of a decentered IOL in the presence of a CTR performed by 1 of 3 surgeons (IIKA, CK, DTW) was done. Demographic information, previous surgical details, slit-lamp and fundoscopic findings, intraocular pressure (IOP), operative notes, and preoperative and postoperative VAs and refraction were evaluated.
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The interval from initial cataract surgery and CTR implantation to decentration was classified as early (within 1 year) or late (beyond 1 year). Decentered CTR–IOL– capsular bag complexes were categorized as those subluxed within the retropupillary space/anterior vitreous and those that were completely dislocated into the posterior vitreous cavity. Statistical analysis was performed using Excel (Microsoft, Inc., Redmond, WA). A 2-tailed distribution t test was used for evaluating differences in mean preoperative and postoperative VAs and refraction. All Snellen VAs were converted to logarithm of the minimum angle of resolution (logMAR) values for statistical analysis.
Results Eleven patients who presented with subluxation or dislocation of a CTR–IOL– capsular bag complex were identified. All patients underwent surgical repositioning. Table 1 summarizes these cases. The mean age (⫾ standard deviation [SD]) of patients at the time of repositioning surgery was 66.1⫾9.8 years, with 5 females and 6 males. All patients had previous phacoemulsification and IOL implantation with in-the-bag CTR for zonular weakness; 3 of these cases were combined with trabeculectomy. In 1 patient (case 6), 2 CTRs were implanted into the capsular bag. Indications for CTR implantation at the time of original surgery were for zonular instability due to diagnoses listed in Table 1. Seven of the 11 patients had underlying pseudoexfoliation syndrome; 4 of these patients had associated glaucoma. Full details of previous surgery and IOL designs were not available for all patients. Ten of the 11 patients (exception: case 4; see below) had a well-centered posterior chamber IOL (PCIOL) within the capsular bag, with a centered capsulorhexis overlying the IOL optic (Fig 1). However, the entire capsular bag complex was decentered. It was noted that, subjectively, there was a greater than expected anterior capsular opacification in these patients,
Ahmed et al 䡠 Postoperative CTR Dislocations Summaries
Operating Room Procedure
Preoperative BCVA Refractive Cylinder†
Postoperative BCVA Refractive Cylinder
3-point scleral suture loop fixation
CF 1.50 D
20/80 0.50 D
PPV ⫹ 2-point scleral suture CTS scleral suture fixation superiorly Single scleral suture loop superiorly 2-point scleral suture loop Single scleral suture loop superiorly Iris fixation of haptics with capsular bag
HM CF 20/200 20/25 20/80 1.00 D 20/40
20/30 20/25 0.75 20/30 0.50 20/25 1.50 20/30 1.00 20/80 0.50
Single scleral suture loop temporally CTS scleral suture fixation superiorly ⫹ MMC trabeculectomy
20/60 20/60 0.50 D
20/30 1.00 D 20/80 0.50 D
PPV ⫹ 2-point scleral suture 3-point scleral suture loop fixation
HM 20/40 0.50 D
20/25 20/30 1.00 D
D D D D D
Comments Required postoperative needling; BCVA limited by advanced glaucoma Postoperative laser capsulotomy Postoperative IOP spike; postoperative laser capsulotomy Postoperative IOP spike Postoperative laser capsulotomy Decentration after trabeculectomy; marked IOP spike required multiple needlings; 2 BCVA due to advanced glaucoma Postoperative laser capsulotomy Marked IOP spike required needlings and later tube-shunt implantation; 2 BCVA due to advanced glaucoma
tension segment; D ⫽ diopters; HM ⫽ hand movements; IOL ⫽ intraocular lens; IOP ⫽ intraocular pressure; MMC ⫽ mitomycin C; PPV ⫽ pars plana
although none had severe phimosis or previous neodymium:yttrium– aluminum– garnet (Nd:YAG) laser anterior capsulotomy relaxing incisions. Four patients (cases 1, 5, 9, and 10) had Nd:YAG laser posterior capsulotomy after initial cataract surgery for posterior capsular opacification (PCO). Although full details were unavailable, capsulotomies were done well before presenting with decentration. Three patients had significant PCO at the time of decentration. The duration from initial surgery to repositioning ranged from 22 days to 74.7 months. Of the 11 patients, 3 were found to have CTR–IOL– capsular bag decentration in the early postoperative period and went on to surgical repositioning at a mean (⫾ SD) duration of 6.1⫾7.9 months after initial cataract surgery. The mean duration for those that developed late decentration was 49.6⫾15.3 months. Cases 4, 8, and 11 involved early decentration noted in the immediately postoperative period after initial cataract surgery. Patient 4, who had an underlying history of pseudoexfoliation, had a CTR placed within the capsular bag at the time of cataract surgery but did not achieve adequate intraoperative centration. The surgeon decided to place a PCIOL in the sulcus space, and the patient was found to have PCIOL and CTR decentration on the first postoperative day examination. Patient 8 developed intraoperative zonular dialysis temporally (subincision), and thus, a CTR and PCIOL were placed within the capsular bag. However, on postoperative day 1, the patient was found to have nasal subluxation. Patient 11, who had a history of combined mechanism glaucoma, was found to have pseudophacodinesis within 2 weeks of surgery and went on to decentration requiring repositioning surgery. Patient 7, who had had previous uneventful phacoemulsification with in-the-bag CTR and PCIOL, was stable until trabeculectomy surgery was performed 49.4 months later. After trabeculectomy, the patient was noted to have pseudophacodinesis, which proceeded to subluxation, thus requiring repositioning surgery. The remaining 7 patients presented with spontaneous delayedonset decentration after initial successful implant surgery. All patients, except 9 and 11, presented with gross decentration
of the CTR–IOL– capsular bag complex. Patients 9 and 11 had pseudophacodinesis, which was progressive and severe, and developed early subluxation and what seemed to be impending dislocation. Two patients, 2 and 10, presented with complete dislocation of the CTR–IOL– capsular bag complex into the posterior vitreous (Fig 1). In the remaining 7 cases, the CTR was subluxed in the retropupillary space/anterior vitreous (Fig 2A): inferiorly (Sunset syndrome) in 4 patients, inferotemporally in 1, anterior vitreous in 1, and nasally in 1.
Surgical Technique The surgical approach was dependent on CTR position. General anesthesia was used in 1 patient, retrobulbar in 2 patients, and topical anesthesia in 8 patients. For cases 2 and 10, in which the CTR–IOL– capsular bag complex had completely dislocated, a standard 3-port pars plana vitrectomy (PPV) was used to free the complex of vitreous adhesions, allowing for levitation with 20-gauge microforceps posterior to the iris plane. With the aid of an assistant, the complex was held in position in the retro-iris plane, while an ab externo scleral suturing technique with double armed 10-0 polypropylene was used as described below. For the remaining 9 patients, in whom the CTR–IOL– capsular bag complex was subluxed in the retropupillary space/anterior vitreous, an anterior approach was taken. In 6 of these patients, an ab externo scleral suturing technique was used, in which 9-0 polypropylene (4 patients) or 10-0 polypropylene (2 patients) was used to loop the CTR through the capsular bag (Fig 2B–F). Micrograsping forceps through a limbal incision were used to support the capsular bag during suture passes. Through a scleral groove 1.5 mm posterior to the limbus, a 26- or 27-gauge cannula was pierced through the sclera and placed under the CTR and then through the peripherally fused anterior and posterior capsules. One needle of a double-armed suture was passed intracamerally and docked into the hypodermic needle, which was then retracted out through the scleral groove, thus placing the suture pass under the
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Ahmed et al 䡠 Postoperative CTR Dislocations
Figure 4. The capsular tension segment in place, within the capsular bag, with a polypropylene suture through the fixation eyelet securing the capsular tension ring–intraocular lens– capsular bag complex to the sclera.
Figure 3. The main body of the capsular tension segment sits within the capsular fornix, with an anteriorly positioned central fixation eyelet that fits anterior to the capsule for scleral suture fixation.
CTR. This process was repeated through an adjacent scleral pass anterior to the CTR and capsule using the other end of the suture, thus creating a suture loop around the CTR. The suture was tightened and knotted, thus securing and recentering the CTR– IOL– capsular bag complex. The knot was then rotated into the scleral groove. Depending on the location and severity of CTR subluxation, multiple points of scleral suture fixation were performed. Single fixation of the CTR was used in 2 cases of Sunset syndrome, as superior fixation was felt to be critical in these cases where the superior zonules seemed to be preferentially involved. In 1 case of nasal subluxation (no. 8), the iatrogenic zonular dialysis localized temporally, and thus, a single scleral suture was used at this position. Two-point scleral suture fixation was used in a patient (no. 5) who had severe inferotemporal CTR subluxation. The scleral sutures were placed superiorly and nasally. Three-point scleral suture fixation was used in 2 patients (nos. 1 and 11) in whom global zonular support was felt to be very poor. The capsular tension segment (CTS) (Morcher GmbH, Stutt-
gart, Germany) (Fig 3), which has been used to reposition subluxed crystalline lenses, was used in 2 patients (nos. 3 and 9). In these cases, the capsular bag was opened with viscoelastic expansion, and the CTS was placed within the peripheral capsular bag superiorly. The anteriorly positioned eyelet, situated anterior to the capsular bag, was fixated with a 9-0 polypropylene suture and passed through a scleral groove made 1.5 mm posterior to the limbus (Fig 4). No sutures were passed through the capsular bag in these cases. A trabeculectomy was also performed as part of the operative procedure in 1 of these patients (no. 9). In one patient (no. 7), who presented with CTR–IOL– capsular bag subluxation after trabeculectomy, a modified McCannel iris suture fixation of the PCIOL haptics was performed to avoid conjunctival manipulation in the presence of a functioning filter. In this case, the CTR and IOL were left in the capsular bag, and needle passes were made through the iris and capsular bag and under each haptic for 2-point iris fixation.
Outcomes After a mean follow-up of 9.1⫾5.2 months, all patients had successful anatomical centration of the CTR–IOL– capsular bag complex after repositioning surgery. One patient had a mild degree of IOL tilt, and 4 patients had residual mild pseudophacodinesis. There were no significant postoperative astigmatic errors (Table 1). Mean preoperative and postoperative VAs and refractive data are presented in Table 2. For statistical analysis, all Snellen VAs were converted to logMAR values. Mean uncorrected VA (P ⫽ 0.012) and best-corrected VA (BCVA) (P ⫽ 0.014) improved
4™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™ Figure 1. Complete dislocation of the capsular tension ring–intraocular lens– capsular bag complex onto the posterior pole. Figure 2. A, Inferior subluxation of the capsular tension ring (CTR)–intraocular lens (IOL)– capsular bag complex. Iris retractors have been used to expand the small pupil. B, Overlying the area of significant zonular dialysis, a 26-gauge hypodermic needle is placed through a superior scleral groove 1.5 mm posterior to the limbus into the eye. The open bore needle is directed under the CTR/bag complex and through the capsule, and is used to dock one needle of a double-armed 9-0 polypropylene suture. C, The docked 9-0 polypropylene needle is pulled through the capsular bag, under the CTR, and out through the scleral groove. D, The same process is repeated anterior to the CTR and capsular bag, using the other end of the double-armed 9-0 polypropylene suture through a common corneal incision. E, With the CTR looped with the 9-0 polypropylene suture, the suture is pulled tight outside the eye, thereby centering the CTR–IOL– capsular bag complex, and a knot is tied and rotated within the scleral groove. F, The CTR–IOL– capsular bag complex is well centered after the suture loop is tied through the scleral groove.
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Ophthalmology Volume 112, Number 10, October 2005 Table 2. Visual Acuity Results UCVA Preoperative Postoperative
BCVA
Refractive Cylinder
Spherical Equivalent
20/200 20/100 0.90 ⫾ 0.50 D ⫹0.53 ⫾ 3.00 D 20/80 20/40 0.80 ⫾ 0.30 D ⫺0.50 ⫾ 0.90 D P ⫽ 0.012 P ⫽ 0.014 P ⫽ 0.8 P ⫽ 0.99
BCVA ⫽ best-corrected visual acuity; D ⫽ diopters; UCVA ⫽ uncorrected visual acuity. Mean ⫾ standard deviation.
postoperatively. After repositioning surgery, BCVA improved in 7 patients, was maintained in 2, and worsened in 2 (due to advanced glaucoma). Three patients had preoperative PCO treated with laser capsulotomy 3 months after repositioning surgery. Five patients, all of whom had pseudoexfoliation syndrome, had postoperative IOP spikes after surgery. This was short lived and medically controlled in 2 of these patients. In 2 patients (nos. 1 and 7), who had a previous conjunctival filter, bleb needling was required for IOP control. In 1 patient (no. 9), in whom a mitomycin-C trabeculectomy had been performed at the time of repositioning surgery, postoperative IOP became uncontrolled despite medications and multiple needlings. A Baerveldt glaucoma drainage device (Advanced Medical Optics, Santa Ana, CA) was implanted 10.2 months later, after which IOP was successfully controlled. In 2 patients (nos. 7 and 9), BCVA decreased after repositioning surgery. Both of these patients had filtering blebs, which developed IOP elevations after surgery requiring bleb needlings. Although IOP was eventually controlled, BCVA declined due to progression of advanced glaucomatous optic neuropathy.
Discussion The advent of the CTR has provided a useful adjunct to phacoemulsification in the presence of zonular weakness. Surgeons are increasingly using it for pseudoexfoliation syndrome, trauma, iatrogenic, postoperative, and congenital zonular laxity. The CTR is effective in providing improved intraoperative support and postoperative centration in mild generalized zonular weakness or localized zonular dialysis. Early follow-up of CTR use in loose zonules found excellent IOL centration 2 to 11 months postoperatively.3 Another study of 21 eyes with zonular dialysis of ⱕ150° found a 90.5% success rate, with 2 eyes ending up with intraoperative extension of dialysis; postoperatively, at a mean follow-up of ⬍1 year, all eyes with a CTR placed had a well-centered IOL within the bag.4 In a comparative study of CTR in pseudoexfoliation eyes, the use of a CTR reduced the risk of intraoperative zonular separation.5 However, there is considerable debate as to the limits of CTR use in more profound zonulopathy, where the Cionni modified variant12 or the Ahmed CTS (Ahmed IK, Kranemann C, Crandall AS. Capsular hemi-ring: next step in effective management of profound zonular dialysis. Film presented at: ASCRS Symposium on Cataract, IOL, and Refractive Surgery Film Festival, April, 2003; San Francisco, California)13— both of which can be suture fixated to
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sclera14— have been proposed as more appropriate devices. Surgeons implanting only the standard CTR in these advanced cases may not achieve adequate capsular bag centration. Another concern is potential further aggravation and extension of zonular loss during the CTR insertion process, particularly when placed before phacoemulsification in cases of a dense cataract and/or profound zonulopathy. This may occur in up to 10% of cases.4 In this current study of 11 eyes with a previously implanted CTR in-the-bag for zonular weakness, CTR–IOL– capsular bag decentration occurred either early (noted on the first postoperative day), in 3 cases, or late (beyond 1 year from surgery), in 8 cases. We highlight that these were 2 distinct groups: early CTR decentrations versus late CTR decentrations. In the early cases, decentration was likely due to inappropriate selection of a capsular tension device at the time of surgery (i.e., standard CTR insufficient for degree of zonular instability) or further iatrogenic trauma to existing zonules. Despite what has been discussed in some circles, a sulcus-supported PCIOL is unlikely to be an appropriate choice in cases of zonular laxity as found in one case. In these situations, the surgeon must make the choice of scleral fixation of a CTR, the use of a CTS, scleral or iris fixation of a PCIOL, or use of an anterior chamber IOL. Each of these options has its own pros and cons, which are beyond the scope of this article. Late-onset spontaneous postoperative capsular bag decentration is a sequela of progressive zonular loss due to underlying pathology, particularly a concern in pseudoexfoliation syndrome.15 Mechanisms of progressive loss of capsular support after cataract surgery are multifactorial and include lens epithelial cell proliferation and capsular contraction, zonulysis from underlying conditions, including pseudoexfoliation syndrome and congenital conditions such as Marfan’s syndrome, and accidental or surgical trauma. In this study, pseudoexfoliation syndrome was implicated in 6 of 8 delayed-onset decentrations, which is consistent with earlier reports of delayed-onset in-the-bag IOL dislocations.15 In a postmortem study of PCIOL centration, eyes with pseudoexfoliation syndrome had IOL decentration greater than that of a group of normals.16 Histopathologically, lysosomal enzymes have been demonstrated within pseudoexfoliation material, indicating a proteolytic mechanism of zonular disintegration.17 In certain susceptible patients, this process is likely to continue and, without intervention, eventually may result in the loss of all zonular support and dislocation of the capsular bag. Delayed spontaneous dislocation of in-the-bag PCIOLs has been reported up to 5 to 10 years after uneventful surgery and has been described in pseudoexfoliation syndrome.15,18 –20 Jehan et al reported 8 eyes with pseudoexfoliation (5 had glaucoma) with previous uncomplicated phacoemulsification and endocapsular PCIOL implantation that developed late spontaneous dislocation 57 to 115 months after surgery.15 The authors suggest that CTR use in these cases may reduce the risk of delayed dislocation in pseudoexfoliation. Some surgeons also advocate the use of a CTR routinely in all pseudoexfoliation patients at the time of cataract surgery.21 Although the use of a CTR has been
Ahmed et al 䡠 Postoperative CTR Dislocations shown to improve IOL centration postoperatively,3–5 these are short-term studies. While, in principle, a CTR may have provided initial support, it is unknown if this would have prevented or delayed late-onset decentration in these progressive cases. Indeed, in our study of 11 patients, 7 of whom had pseudoexfoliation syndrome, postoperative PCIOL decentration occurred despite the use of a standard CTR, requiring intervention from 22 days to 6.3 years after initial implantation. Although the mean interval to displacement for lateonset CTR decentration was 49.6 months—a fair amount of time since initial implantation—this is shorter than the reported interval for delayed-onset PCIOL dislocation in pseudoexfoliation syndrome.15,19 This may be due to the presence of greater zonular instability in these more susceptible patients (necessitating CTR use in the first place). We were surprised to find that 2 cases of traumatic zonular damage, typically a nonprogressive condition, developed later-onset decentration. We suspect that they may have had initial extensive dialysis that may not have been suitable for a standard CTR. Delayed subluxation also may have been due to the fact that both of these patients were younger (⬍60 years) and perhaps at greater risk for lens epithelial cell proliferation and capsular contracture in an already compromised capsulozonular complex. It is also interesting to note that the placement of 2 CTRs within the bag in an attempt to provide additional support in one of these patients, as has been suggested by others,22 did not prevent late-onset decentration. Of the 9 patients with subluxation, 8 subluxed so inferiorly, thus indicating greater loss of superior zonular support and resultant decentration. Superior zonular support seems to be a critical factor in maintaining IOL centration, consistent with what was found in delayed spontaneous PCIOL dislocation in pseudoexfoliation, where Jehan et al found that 6 of 8 patients had inferior dislocation.15 We suspect that the superior zonules either are at greatest risk of damage, possibly related to gravity, or are affected preferentially in the disease process. It is also possible that they were more likely to be damaged at the time of the initial surgery, because most of these older cases were of phacoemulsification through a superior incision using a grooving technique that would have created the greatest stress subincisionally (superiorly). Most of the patients in our series were found to have a well-centered PCIOL within the capsular bag, with a centered continuous curvilinear capsulorrhexis (CCC). This would indicate that the CTR is very effective in redistributing and equalizing circumferential zonular tension around the capsular bag. However, when the remaining zonules are (or become) insufficient to provide adequate global support, the capsular bag itself is at risk of decentration. Centripetal capsular contraction—symmetric or asymmetric— of the CCC and continual traction on already weakened zonules may be associated with progressive zonular loss, IOL decentration, and capsular bag dehiscence.19,23,24 Although rarely found in can-opener–style capsulotomies, since the advent of the CCC it has become more frequent. Treating the capsular contracture with Nd:YAG laser radial anterior relaxing incisions has been found to be an effective
prevention against IOL dislocation.24 Contrary to the initial theory, CTRs do not necessarily prevent capsular contraction or phimosis; these are more likely to occur with a smaller size ring.25 Capsular contraction syndrome, which is more likely to occur with pseudoexfoliation, older age, weak zonules, and metaplastic proliferation of lens epithelial cells, has been reported to result in IOL decentration even in the presence of an endocapsular tension ring.26 –29 Neodymium:YAG laser anterior capsule relaxing incisions were performed to stabilize these cases. Although subjectively we found a greater amount of anterior capsular opacification than expected, none of the patients in our study had previous laser anterior capsulotomies. Preemptive early Nd: YAG laser treatment given to the contracting anterior capsule and CCC may be an appropriate preventative step in these cases. Unfortunately, other than assessing the degree of instability at the time of surgery and, perhaps, the degree of capsular contraction, there is likely little that surgeons can do to predict those patients who may go on to develop late spontaneous decentration. However, as has been suggested,30 we do feel that new-onset or worsening pseudophacodinesis in susceptible eyes may be a sign of impending decentration. The constant motion of the IOL/capsular bag in pseudophacodinesis may cause progressive shearing of existing zonules over time. In fact, in 2 cases in our series this was an indication for surgical intervention. In the future, the ultrasound biomicroscopy, which has been a useful tool in identifying focal areas of zonular loss,31,32 may be adapted to correlate zonular status with the future risk of decentration better. There is little in the published literature on the incidence of in-the-bag CTR dislocation and its management. In one case report, an ab externo suture repositioning was successfully performed for a dislocated CTR complex after severe coughing.10 In another case report, after CTR implantation in a child with Marfan’s syndrome the patient developed postoperative decentration requiring multiple revisions.11 Recent case reports have described removal techniques of a posterior dislocated CTR within the vitreous body due to intraoperative posterior capsule breakage.6 –9 Although CTR removal and IOL exchange is an option in these cases, removal may cause excessive tissue trauma and larger incisions, and explanation typically requires increased manipulations and complications. The exchange IOL would need an anterior chamber IOL or iris-fixated or scleral-sutured PCIOL—all of which have potential problems, especially in glaucoma patients. Principles of the repositioning of CTR decentrations are similar to those of surgical repositioning of displaced PCIOLs. Surgical technique, in terms of an anterior or posterior approach, should be based on whether the CTR–IOL– capsular bag complex is subluxed in the retropupillary/anterior vitreous space or dislocated into the posterior vitreous. For completely dislocated CTRs in the vitreous cavity, we suggest a PPV to free the CTR–IOL– capsular bag complex from the vitreous, with subsequent suturing of the CTR to the sclera. Although this requires temporary stabilization of the complex in the retropupillary space, the use of microforceps, capsule retractors, and creative needle passes makes this possible.
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Ophthalmology Volume 112, Number 10, October 2005 In the case of subluxed CTR–IOL– capsular bag complexes accessible via an anterior segment approach, scleral fixation of the complex with the use of polypropylene suture passes is an excellent method of recentration and support. We prefer the control and precision of the ab externo suturing technique. The presence of a CTR greatly facilitates capturing the capsular bag. Although there is the potential for capsular tearing and extension with needle passes made through a fresh capsule,33 we do not feel that this is a major issue with postoperative fibrotic and fused capsules. The CTS, which has emerged as a useful device and implant for the management of the dislocated crystalline lens, seems to provide an alternative to needle passage through the capsule in cases of IOL/CTR decentration as well. With reopening of the superior fornix of the capsular bag, the CTS can be suture fixated to the sclera. Considering that the need for superior capsular bag support was critical in the majority of postoperative IOL and CTR subluxations, most of the patients in our study had either direct fixation of the CTR or placement of a CTS to the superior sclera in these cases. We recommend the use of a higher tensile strength suture like 9-0 polypropylene, as opposed to 10-0 polypropylene, to prevent postoperative suture breakage. Our case series’ results show that it is possible to salvage the CTR–IOL– capsular bag complex with suture fixation. The majority of patients had improvements in VA with satisfactory centration after surgical repositioning, with minimal astigmatic error or significant IOL tilting. As our current study presents short- to medium-term results, further follow-up is required to determine long-term success, including issues of potential late-onset suture breakage. However, these patients often have concomitant pseudoexfoliative glaucoma, and in this series, 2 patients progressed with advanced glaucoma resulting in further visual loss, thus stressing the need for caution. Whether an advanced glaucoma disease state is related to the severity of zonular loss or whether the complexity of the surgical repositioning procedure is too great an insult for these compromised eyes is uncertain. We suggest careful preparation and postoperative monitoring in these eyes undergoing further surgery. In summary, postoperative subluxation or dislocation of a previously implanted CTR and IOL– capsular bag complex may occur due to inadequate underlying zonular support for a standard CTR or aggressive capsular contracture and/or progressive zonulysis. Capsular tension rings embody an attempt to maximize existing capsular bag support, but they do not halt the underlying metabolic or disease process in zonulysis. This seems to be of particular concern in pseudoexfoliation syndrome. To our knowledge, this is the first published series describing in-the-bag CTR decentration and its management with surgical repositioning. Based on our findings, one may question the value of CTR implantation at all in cases of zonular weakness. However, an alternative view may be that the CTR may have prevented intraoperative complications and delayed dislocation, and permitted surgical repositioning to be performed in some cases. The value of the CTR for intraoper-
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ative support in mild zonular weakness has been established. Although not completely preventative, the CTR seems to limit capsular contraction and asymmetric capsular bag and IOL displacement. Furthermore, in the event of postoperative decentration we feel that surgical repositioning is more easily accomplished in the presence of a CTR, which, acting as a backbone, may be directly sutured through the capsule to the sclera. We also know that there has been a large number of patients—the vast majority—in whom CTR implantation has maintained adequate centration. However, this may be due to the long interval to presentation and the fact that CTRs were introduced within the last 10 years. Clearly, at this time there are insufficient data to determine the true incidence of CTR decentration and the long-term benefit of CTR use in progressive cases of zonulysis. For these reasons, we encourage surgeons to consider the CTR—for both intraoperative and postoperative support—in cases of zonular weakness, but suggest using careful implantation techniques to prevent further zonular loss and caution in cases of more advanced zonulopathy, in which a sutured capsular tension device or alternative IOL fixation should be considered. Surgeons who employ the CTR must evaluate capsular bag stability intraoperatively and, if necessary, need to be facile in suturing techniques at the time of primary surgery should it be deemed that a standard CTR alone is insufficient. It is our opinion that simply inserting a second or even third CTR will not provide substantially extra support, as was found in one patient in this study. In these cases, either direct suturing of the standard CTR through the capsule31,34,35 or placement of modified CTR or CTS device(s) at the time of cataract surgery would be indicated. Multiple factors are likely involved in the prevention of capsular bag and IOL dislocation in patients with zonular weakness. These include a gentle zonule-friendly phacoemulsification technique, generous size capsulorrhexis, meticulous cortical cleanup and anterior capsule polishing, large CTR, use of an acrylic IOL (least anterior capsular opacification),36 –38 and intensive topical steroids and nonsteroidal antiinflammatory drugs postoperatively to treat inflammation. The importance of long-term postoperative observation for progressive zonulopathy must be stressed. Although these cases are relatively uncommon, they should be managed at the first signs of capsular contracture with early radial Nd:YAG laser anterior capsulotomy. At the first signs of instability, such as pseudophacodinesis, or progressive IOL decentration, surgical intervention should be considered to minimize the need for more invasive methods and/or vitrectomy. Certainly the CTR and its derivatives have been an exciting development in phacoemulsification of the complex cataract. Surgeons are still learning about the long-term implication of in-the-bag placement of a PCIOL and/or CTR in certain zonular conditions, particularly pseudoexfoliation. This study sheds some light on this issue and provides a surgical approach to manage decentered CTRs. Despite the theoretical advantages of a CTR in progressive zonulopathy like pseudoexfoliation syndrome, a standard
Ahmed et al 䡠 Postoperative CTR Dislocations CTR may not fully prevent late-onset dislocation. Further controlled studies are needed to assess the value of routine CTR placement in pseudoexfoliation syndrome, to select an appropriate capsular tension device, to assess the incidence of CTR decentration, and to select the proper approach to managing CTR subluxations or dislocations.
References
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1. Hara T, Hara T, Yamada Y. “Equator ring” for maintenance of the completely circular contour of the capsular bag equator after cataract removal. Ophthalmic Surg 1991;22:358 –9. 2. Nagamato T, Bissen-Miyajima H. A ring to support the capsular bag after continuous curvilinear capsulorrhexis. J Cataract Refract Surg 1994;20:417–20. 3. 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. 4. Jacob S, Agarwal A, Agarwal A, et al. Efficacy of a capsular tension ring for phacoemulsification in eyes with zonular dialysis. J Cataract Refract Surg 2003;29:315–21. 5. Bayraktar S, Altan T, Kucuksumer Y, Yilmaz OF. Capsular tension ring implantation after capsulorhexis in phacoemulsification of cataracts associated with pseudoexfoliation syndrome. Intraoperative complications and early postoperative findings. J Cataract Refract Surg 2001;27:1620 – 8. 6. Bopp S, Lucke K. Chronic cystoid macular edema in an eye with a capsule defect and posteriorly dislocated capsular tension ring. J Cataract Refract Surg 2003;29:603– 8. 7. Lang Y, Fineberg E, Garzozi HJ. Vitrectomy to remove a posteriorly dislocated endocapsular tension ring. J Cataract Refract Surg 2001;27:474 – 6. 8. Ma PE, Kaur H, Petrovic V, Hay D. Technique for removal of a capsular tension ring from the vitreous. Ophthalmology 2003;110:1142– 4. 9. Bhattacharjee H, Bhattacharjee K, Das D, et al. Management of a posteriorly dislocated endocapsular tension ring and a foldable acrylic intraocular lens. J Cataract Refract Surg 2004; 30:243– 6. 10. Moreno-Montanes J, Heras H, Fernandez-Hortelano A. Surgical treatment of a dislocated intraocular lens-capsular bagcapsular tension ring complex. J Cataract Refract Surg 2005; 31:270 –3. 11. Dietlein TS, Jacobi PC, Konen W, Krieglstein GK. Complications of endocapsular tension ring implantation in a child with Marfan’s syndrome. J Cataract Refract Surg 2000;26: 937– 40. 12. 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. 13. Ahmed II. Consultation. J Cataract Refract Surg 2004;30: 2041–2. 14. Ahmed II, Crandall AS. Ab externo scleral fixation of the Cionni modified capsular tension ring. J Cataract Refract Surg 2001;97:977– 81. 15. Jehan FS, Mamalis N, Crandall AS. Spontaneous late dislocation of intraocular lens within the capsular bag in pseudoexfoliation patients. Ophthalmology 2001;108:1727–31. 16. Auffarth GU, Tsao K, Wesendhal 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;75:463–7. 17. Schlotzer-Schrehardt U, Naumann GO. A histopathologic
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study of zonular instability in pseudoexfoliation syndrome. Am J Ophthalmol 1994;118:730 – 43. Shigeeda T, Nagahara M, Kato S, et al. Spontaneous posterior dislocation of intraocular lenses fixated in the capsular bag. J Cataract Refract Surg 2002;28:1689 –93. Masket S, Osher RH. Late complications with intraocular lens dislocation after capsulorhexis in pseudoexfoliation syndrome. J Cataract Refract Surg 2002;28:1481– 4. Gross JG, Kokame GT, Weinberg DV, et al. In-the-bag intraocular lens dislocation. Am J Ophthalmol 2004;137:630 –5. Fine IH. The capsular tension ring: indications for use. Cataract Refract Surg Today 2005;(suppl):13– 4. Liu CS, Eleftheriadis H. Multiple capsular tension rings for the prevention of capsular contraction syndrome [letter]. J Cataract Refract Surg 2001;27:342–3. Guthoff R, Abramo F, Draeger J, et al. Forces on intraocular lens haptics induced by capsular fibrosis: an experimental study. Graefes Arch Clin Exp Ophthalmol 1990;228:363– 8. Davison JA. Capsule contraction syndrome. J Cataract Refract Surg 1993;19:582–9. Strenn K, Menapace R, Vass C. Capsular bag shrinkage after implantation of an open-loop silicone lens and a poly(methyl methacrylate) capsule tension ring. J Cataract Refract Surg 1997;23:1543–7. Waheed K, Eleftheriadis H, Liu C. Anterior capsular phimosis in eyes with a capsular tension ring. J Cataract Refract Surg 2001;27:1688 –90. Faschinger CW, Eckhardt M. Complete capsulorhexis opening occlusion despite capsular tension ring implantation. J Cataract Refract Surg 1999;25:1013–5. Sudhir RR, Rao SK. Capsulorhexis phimosis in retinitis pigmentosa despite capsular tension ring implantation. J Cataract Refract Surg 2001;27:1691– 4. Moreno-Montanes J, Sanchez-Tocino H, Rodriguez-Condo R. Complete anterior capsule contraction alter phacoemulsification with acrylic intraocular lens and endocapsular ring implantation. J Cataract Refract Surg 2002;28:717–9. Moreno-Montanes J, Rodriguez-Conde R. Capsular tension ring in eyes with pseudoexfoliation [letter]. J Cataract Refract Surg 2002;28:2241–2. Pavlin CJ, Buys YM, Pathmanathan T. Imaging zonular abnormalities using ultrasound biomicroscopy. Arch Ophthalmol 1998;116:854 –7. McWhae JA, Crichton AC, Rinke M. Ultrasound biomicroscopy for the assessment of zonules after ocular trauma. Ophthalmology 2003;110:1340 –3. Lam DS, Young AL, Leung AT, et al. Scleral fixation of a capsular tension ring for severe ectopia lentis. J Cataract Refract Surg 2000;26:609 –12. Osher R. New approach: synthetic zonules [video]. Video J Cataract Refract Surg 1997;13(1). Pfeifer V, Villarkuri J. Suturing the ring. Video J Cataract Refract Surg 1998;14(4). Cochener B, Jacq PL, Colin J. Capsule contraction after continuous curvilinear capsulorrhexis: poly(methyl methacrylate) versus silicone intraocular lenses. J Cataract Refract Surg 1999;25:1362–9. Ursell PG, Spalton DJ, Pande MV. Anterior capsule stability in eyes with intraocular lenses made of poly(methyl methacrylate), silicone, and AcrySof. J Cataract Refract Surg 1997; 23:1532– 8. Sacu S, Menapace R, Buehl W, et al. Effect of intraocular lens optic edge design and material on fibrotic capsule opacification and capsulorhexis contraction. J Cataract Refract Surg 2004;30:1875– 82.
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The capsular tension ring (CTR), described initially by Hara et al1 and Nagamoto and Bissen-Miyajima2 and further developed by Witschel and Legler (Legler U, Witschel B. The capsular ring: a new device for complicated cataract surgery. Film presented at: American Society of Cataract and Refractive Surgery [ASCRS] Symposium on Cataract, IOL, and Refractive Surgery, May, 1993; Seattle, Washington), provides stabilization of the capsular bag and intraocular lens (IOL) during and after cataract surgery in cases of zonular instability. The circular polymethyl methacrylate
Originally received: January 2, 2005. Accepted: May 9, 2005. Manuscript no. 2005-3. 1 University of Toronto, Toronto, Canada. 2 University of Utah, Salt Lake City, Utah. 3 McGill University, Montreal, Canada. The authors have no financial interest in any of the products discussed in the article. Correspondence and reprint requests to Iqbal Ike K. Ahmed, MD, Credit Valley EyeCare, 3200 Erin Mills Parkway, Unit 1, Mississauga, Ontario, L5L 1W8, Canada. E-mail: [email protected]. © 2005 by the American Academy of Ophthalmology Published by Elsevier Inc.
open-ended filament is placed within an intact capsular bag to buttress areas of poor zonular support while recruiting and redistributing tension from existing zonules circumferentially. The CTR is placed at the time of initial surgery and is maintained at the capsular equator for postoperative centration. Early results show that, for mild generalized zonular weakness or localized zonular dialysis (i.e., ⱕ4 clock hours), the CTR provides adequate support for in-the-bag IOL centration.3–5 Although data are currently unavailable on long-term efficacy, it is felt CTR placement may prevent late-onset decentration in high-risk eyes. Indications include pseudoexfoliation syndrome; trauma; and postoperative, iatrogenic, and congenital conditions. Cataract surgeons have benefited from the use of the CTR for complex zonular cases, thus increasing its popularity. Standard CTRs do not necessarily recenter an already severely subluxed or dislocated lens in profound zonulopathy. Furthermore, many zonular conditions are progressive, and although the CTR can provide initial support, some patients may suffer late-onset CTR dislocation. This may ISSN 0161-6420/05/$–see front matter doi:10.1016/j.ophtha.2005.05.006
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Ophthalmology Volume 112, Number 10, October 2005 Table 1. Case
No.
Age (yrs) Gender
1
72 M
PXG
Phacoemulsification/trabeculectomy/IOL/CTR 60.0
Anterior vitreous
2 3 4 5 6 7
54 F 70 M 72 M 47 M 58 M 79 F
PXF PXG PXF Trauma Trauma PXG
Phacoemulsification/IOL/CTR 41.9 Phacoemulsification/IOL/CTR 37.4 Phacoemulsification/IOL/CTR 0.7 Phacoemulsification/IOL/CTR 74.7 Phacoemulsification/IOL/CTR ⫻2 24.1 Phacoemulsification/trabeculectomy/IOL/CTR 55.4
Posterior vitreous Sunset, anterior vitreous Sunset, anterior vitreous Inferotemporal Sunset, anterior vitreous Sunset, anterior vitreous
8 9
69 F 76 F
Iatrogenic PXG
Phacoemulsification/IOL/CTR 2.5 Phacoemulsification/IOL/CTR 52.3
10 11
61 F 69 M
PXF CMG
Phacoemulsification/IOL/CTR 51.0 Phacoemulsification/trabeculectomy/IOL/CTR 15.2
Nasal Marked pseudophacodinests slight sunset Posterior vitreous Marked pseudophacodinesis slight sunset
Diagnosis
Original Surgery Duration (mos)
CTR/IOL Position*
BCVA ⫽ best-corrected visual acuity; CF ⫽ counting fingers; CMG ⫽ combined mechanism glaucoma; CTR ⫽ capsular tension ring; CTS ⫽ capsular vitrectomy; PXF ⫽ pseudoexfoliation syndrome; PXG ⫽ pseudoexfoliation glaucoma. *CTR within capsular bag in all cases. † If applicable.
lead to reduced visual acuity (VA), uveitis, and cystoid macular edema.6 Dislocation of a CTR during a surgical complication and in the presence of a posterior capsular rent has been reported. Management in these cases involves removal of the displaced CTR and/or IOL.6 –9 With early case reports and, perhaps, impending problems as CTR use increases, little has been published on decentered in-the-bag CTRs due to profound zonulysis or progressive zonular weakness (Kranemann C. Late subluxation of capsular tension ring. Poster presented at: ASCRS Symposium on Cataract, IOL, and Refractive Surgery, April, 2003; San Francisco, California).10,11 Decentered inthe-bag CTRs may be categorized as those subluxed within the retropupillary space/anterior vitreous and those that have dislocated into the posterior vitreous cavity. Although CTR removal and IOL exchange is an option in these cases, our preference has been to maintain a closed-system minimally invasive approach of surgical repositioning with suture fixation. We are unaware of any published series on features, operative techniques, or results of management of CTR decentration with surgical repositioning. Here we report details and the management of subluxed or dislocated CTR–IOL– capsular bag using repositioning techniques.
Materials and Methods A retrospective chart review of 11 patients who underwent surgical repositioning of a decentered IOL in the presence of a CTR performed by 1 of 3 surgeons (IIKA, CK, DTW) was done. Demographic information, previous surgical details, slit-lamp and fundoscopic findings, intraocular pressure (IOP), operative notes, and preoperative and postoperative VAs and refraction were evaluated.
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The interval from initial cataract surgery and CTR implantation to decentration was classified as early (within 1 year) or late (beyond 1 year). Decentered CTR–IOL– capsular bag complexes were categorized as those subluxed within the retropupillary space/anterior vitreous and those that were completely dislocated into the posterior vitreous cavity. Statistical analysis was performed using Excel (Microsoft, Inc., Redmond, WA). A 2-tailed distribution t test was used for evaluating differences in mean preoperative and postoperative VAs and refraction. All Snellen VAs were converted to logarithm of the minimum angle of resolution (logMAR) values for statistical analysis.
Results Eleven patients who presented with subluxation or dislocation of a CTR–IOL– capsular bag complex were identified. All patients underwent surgical repositioning. Table 1 summarizes these cases. The mean age (⫾ standard deviation [SD]) of patients at the time of repositioning surgery was 66.1⫾9.8 years, with 5 females and 6 males. All patients had previous phacoemulsification and IOL implantation with in-the-bag CTR for zonular weakness; 3 of these cases were combined with trabeculectomy. In 1 patient (case 6), 2 CTRs were implanted into the capsular bag. Indications for CTR implantation at the time of original surgery were for zonular instability due to diagnoses listed in Table 1. Seven of the 11 patients had underlying pseudoexfoliation syndrome; 4 of these patients had associated glaucoma. Full details of previous surgery and IOL designs were not available for all patients. Ten of the 11 patients (exception: case 4; see below) had a well-centered posterior chamber IOL (PCIOL) within the capsular bag, with a centered capsulorhexis overlying the IOL optic (Fig 1). However, the entire capsular bag complex was decentered. It was noted that, subjectively, there was a greater than expected anterior capsular opacification in these patients,
Ahmed et al 䡠 Postoperative CTR Dislocations Summaries
Operating Room Procedure
Preoperative BCVA Refractive Cylinder†
Postoperative BCVA Refractive Cylinder
3-point scleral suture loop fixation
CF 1.50 D
20/80 0.50 D
PPV ⫹ 2-point scleral suture CTS scleral suture fixation superiorly Single scleral suture loop superiorly 2-point scleral suture loop Single scleral suture loop superiorly Iris fixation of haptics with capsular bag
HM CF 20/200 20/25 20/80 1.00 D 20/40
20/30 20/25 0.75 20/30 0.50 20/25 1.50 20/30 1.00 20/80 0.50
Single scleral suture loop temporally CTS scleral suture fixation superiorly ⫹ MMC trabeculectomy
20/60 20/60 0.50 D
20/30 1.00 D 20/80 0.50 D
PPV ⫹ 2-point scleral suture 3-point scleral suture loop fixation
HM 20/40 0.50 D
20/25 20/30 1.00 D
D D D D D
Comments Required postoperative needling; BCVA limited by advanced glaucoma Postoperative laser capsulotomy Postoperative IOP spike; postoperative laser capsulotomy Postoperative IOP spike Postoperative laser capsulotomy Decentration after trabeculectomy; marked IOP spike required multiple needlings; 2 BCVA due to advanced glaucoma Postoperative laser capsulotomy Marked IOP spike required needlings and later tube-shunt implantation; 2 BCVA due to advanced glaucoma
tension segment; D ⫽ diopters; HM ⫽ hand movements; IOL ⫽ intraocular lens; IOP ⫽ intraocular pressure; MMC ⫽ mitomycin C; PPV ⫽ pars plana
although none had severe phimosis or previous neodymium:yttrium– aluminum– garnet (Nd:YAG) laser anterior capsulotomy relaxing incisions. Four patients (cases 1, 5, 9, and 10) had Nd:YAG laser posterior capsulotomy after initial cataract surgery for posterior capsular opacification (PCO). Although full details were unavailable, capsulotomies were done well before presenting with decentration. Three patients had significant PCO at the time of decentration. The duration from initial surgery to repositioning ranged from 22 days to 74.7 months. Of the 11 patients, 3 were found to have CTR–IOL– capsular bag decentration in the early postoperative period and went on to surgical repositioning at a mean (⫾ SD) duration of 6.1⫾7.9 months after initial cataract surgery. The mean duration for those that developed late decentration was 49.6⫾15.3 months. Cases 4, 8, and 11 involved early decentration noted in the immediately postoperative period after initial cataract surgery. Patient 4, who had an underlying history of pseudoexfoliation, had a CTR placed within the capsular bag at the time of cataract surgery but did not achieve adequate intraoperative centration. The surgeon decided to place a PCIOL in the sulcus space, and the patient was found to have PCIOL and CTR decentration on the first postoperative day examination. Patient 8 developed intraoperative zonular dialysis temporally (subincision), and thus, a CTR and PCIOL were placed within the capsular bag. However, on postoperative day 1, the patient was found to have nasal subluxation. Patient 11, who had a history of combined mechanism glaucoma, was found to have pseudophacodinesis within 2 weeks of surgery and went on to decentration requiring repositioning surgery. Patient 7, who had had previous uneventful phacoemulsification with in-the-bag CTR and PCIOL, was stable until trabeculectomy surgery was performed 49.4 months later. After trabeculectomy, the patient was noted to have pseudophacodinesis, which proceeded to subluxation, thus requiring repositioning surgery. The remaining 7 patients presented with spontaneous delayedonset decentration after initial successful implant surgery. All patients, except 9 and 11, presented with gross decentration
of the CTR–IOL– capsular bag complex. Patients 9 and 11 had pseudophacodinesis, which was progressive and severe, and developed early subluxation and what seemed to be impending dislocation. Two patients, 2 and 10, presented with complete dislocation of the CTR–IOL– capsular bag complex into the posterior vitreous (Fig 1). In the remaining 7 cases, the CTR was subluxed in the retropupillary space/anterior vitreous (Fig 2A): inferiorly (Sunset syndrome) in 4 patients, inferotemporally in 1, anterior vitreous in 1, and nasally in 1.
Surgical Technique The surgical approach was dependent on CTR position. General anesthesia was used in 1 patient, retrobulbar in 2 patients, and topical anesthesia in 8 patients. For cases 2 and 10, in which the CTR–IOL– capsular bag complex had completely dislocated, a standard 3-port pars plana vitrectomy (PPV) was used to free the complex of vitreous adhesions, allowing for levitation with 20-gauge microforceps posterior to the iris plane. With the aid of an assistant, the complex was held in position in the retro-iris plane, while an ab externo scleral suturing technique with double armed 10-0 polypropylene was used as described below. For the remaining 9 patients, in whom the CTR–IOL– capsular bag complex was subluxed in the retropupillary space/anterior vitreous, an anterior approach was taken. In 6 of these patients, an ab externo scleral suturing technique was used, in which 9-0 polypropylene (4 patients) or 10-0 polypropylene (2 patients) was used to loop the CTR through the capsular bag (Fig 2B–F). Micrograsping forceps through a limbal incision were used to support the capsular bag during suture passes. Through a scleral groove 1.5 mm posterior to the limbus, a 26- or 27-gauge cannula was pierced through the sclera and placed under the CTR and then through the peripherally fused anterior and posterior capsules. One needle of a double-armed suture was passed intracamerally and docked into the hypodermic needle, which was then retracted out through the scleral groove, thus placing the suture pass under the
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Ahmed et al 䡠 Postoperative CTR Dislocations
Figure 4. The capsular tension segment in place, within the capsular bag, with a polypropylene suture through the fixation eyelet securing the capsular tension ring–intraocular lens– capsular bag complex to the sclera.
Figure 3. The main body of the capsular tension segment sits within the capsular fornix, with an anteriorly positioned central fixation eyelet that fits anterior to the capsule for scleral suture fixation.
CTR. This process was repeated through an adjacent scleral pass anterior to the CTR and capsule using the other end of the suture, thus creating a suture loop around the CTR. The suture was tightened and knotted, thus securing and recentering the CTR– IOL– capsular bag complex. The knot was then rotated into the scleral groove. Depending on the location and severity of CTR subluxation, multiple points of scleral suture fixation were performed. Single fixation of the CTR was used in 2 cases of Sunset syndrome, as superior fixation was felt to be critical in these cases where the superior zonules seemed to be preferentially involved. In 1 case of nasal subluxation (no. 8), the iatrogenic zonular dialysis localized temporally, and thus, a single scleral suture was used at this position. Two-point scleral suture fixation was used in a patient (no. 5) who had severe inferotemporal CTR subluxation. The scleral sutures were placed superiorly and nasally. Three-point scleral suture fixation was used in 2 patients (nos. 1 and 11) in whom global zonular support was felt to be very poor. The capsular tension segment (CTS) (Morcher GmbH, Stutt-
gart, Germany) (Fig 3), which has been used to reposition subluxed crystalline lenses, was used in 2 patients (nos. 3 and 9). In these cases, the capsular bag was opened with viscoelastic expansion, and the CTS was placed within the peripheral capsular bag superiorly. The anteriorly positioned eyelet, situated anterior to the capsular bag, was fixated with a 9-0 polypropylene suture and passed through a scleral groove made 1.5 mm posterior to the limbus (Fig 4). No sutures were passed through the capsular bag in these cases. A trabeculectomy was also performed as part of the operative procedure in 1 of these patients (no. 9). In one patient (no. 7), who presented with CTR–IOL– capsular bag subluxation after trabeculectomy, a modified McCannel iris suture fixation of the PCIOL haptics was performed to avoid conjunctival manipulation in the presence of a functioning filter. In this case, the CTR and IOL were left in the capsular bag, and needle passes were made through the iris and capsular bag and under each haptic for 2-point iris fixation.
Outcomes After a mean follow-up of 9.1⫾5.2 months, all patients had successful anatomical centration of the CTR–IOL– capsular bag complex after repositioning surgery. One patient had a mild degree of IOL tilt, and 4 patients had residual mild pseudophacodinesis. There were no significant postoperative astigmatic errors (Table 1). Mean preoperative and postoperative VAs and refractive data are presented in Table 2. For statistical analysis, all Snellen VAs were converted to logMAR values. Mean uncorrected VA (P ⫽ 0.012) and best-corrected VA (BCVA) (P ⫽ 0.014) improved
4™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™ Figure 1. Complete dislocation of the capsular tension ring–intraocular lens– capsular bag complex onto the posterior pole. Figure 2. A, Inferior subluxation of the capsular tension ring (CTR)–intraocular lens (IOL)– capsular bag complex. Iris retractors have been used to expand the small pupil. B, Overlying the area of significant zonular dialysis, a 26-gauge hypodermic needle is placed through a superior scleral groove 1.5 mm posterior to the limbus into the eye. The open bore needle is directed under the CTR/bag complex and through the capsule, and is used to dock one needle of a double-armed 9-0 polypropylene suture. C, The docked 9-0 polypropylene needle is pulled through the capsular bag, under the CTR, and out through the scleral groove. D, The same process is repeated anterior to the CTR and capsular bag, using the other end of the double-armed 9-0 polypropylene suture through a common corneal incision. E, With the CTR looped with the 9-0 polypropylene suture, the suture is pulled tight outside the eye, thereby centering the CTR–IOL– capsular bag complex, and a knot is tied and rotated within the scleral groove. F, The CTR–IOL– capsular bag complex is well centered after the suture loop is tied through the scleral groove.
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Ophthalmology Volume 112, Number 10, October 2005 Table 2. Visual Acuity Results UCVA Preoperative Postoperative
BCVA
Refractive Cylinder
Spherical Equivalent
20/200 20/100 0.90 ⫾ 0.50 D ⫹0.53 ⫾ 3.00 D 20/80 20/40 0.80 ⫾ 0.30 D ⫺0.50 ⫾ 0.90 D P ⫽ 0.012 P ⫽ 0.014 P ⫽ 0.8 P ⫽ 0.99
BCVA ⫽ best-corrected visual acuity; D ⫽ diopters; UCVA ⫽ uncorrected visual acuity. Mean ⫾ standard deviation.
postoperatively. After repositioning surgery, BCVA improved in 7 patients, was maintained in 2, and worsened in 2 (due to advanced glaucoma). Three patients had preoperative PCO treated with laser capsulotomy 3 months after repositioning surgery. Five patients, all of whom had pseudoexfoliation syndrome, had postoperative IOP spikes after surgery. This was short lived and medically controlled in 2 of these patients. In 2 patients (nos. 1 and 7), who had a previous conjunctival filter, bleb needling was required for IOP control. In 1 patient (no. 9), in whom a mitomycin-C trabeculectomy had been performed at the time of repositioning surgery, postoperative IOP became uncontrolled despite medications and multiple needlings. A Baerveldt glaucoma drainage device (Advanced Medical Optics, Santa Ana, CA) was implanted 10.2 months later, after which IOP was successfully controlled. In 2 patients (nos. 7 and 9), BCVA decreased after repositioning surgery. Both of these patients had filtering blebs, which developed IOP elevations after surgery requiring bleb needlings. Although IOP was eventually controlled, BCVA declined due to progression of advanced glaucomatous optic neuropathy.
Discussion The advent of the CTR has provided a useful adjunct to phacoemulsification in the presence of zonular weakness. Surgeons are increasingly using it for pseudoexfoliation syndrome, trauma, iatrogenic, postoperative, and congenital zonular laxity. The CTR is effective in providing improved intraoperative support and postoperative centration in mild generalized zonular weakness or localized zonular dialysis. Early follow-up of CTR use in loose zonules found excellent IOL centration 2 to 11 months postoperatively.3 Another study of 21 eyes with zonular dialysis of ⱕ150° found a 90.5% success rate, with 2 eyes ending up with intraoperative extension of dialysis; postoperatively, at a mean follow-up of ⬍1 year, all eyes with a CTR placed had a well-centered IOL within the bag.4 In a comparative study of CTR in pseudoexfoliation eyes, the use of a CTR reduced the risk of intraoperative zonular separation.5 However, there is considerable debate as to the limits of CTR use in more profound zonulopathy, where the Cionni modified variant12 or the Ahmed CTS (Ahmed IK, Kranemann C, Crandall AS. Capsular hemi-ring: next step in effective management of profound zonular dialysis. Film presented at: ASCRS Symposium on Cataract, IOL, and Refractive Surgery Film Festival, April, 2003; San Francisco, California)13— both of which can be suture fixated to
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sclera14— have been proposed as more appropriate devices. Surgeons implanting only the standard CTR in these advanced cases may not achieve adequate capsular bag centration. Another concern is potential further aggravation and extension of zonular loss during the CTR insertion process, particularly when placed before phacoemulsification in cases of a dense cataract and/or profound zonulopathy. This may occur in up to 10% of cases.4 In this current study of 11 eyes with a previously implanted CTR in-the-bag for zonular weakness, CTR–IOL– capsular bag decentration occurred either early (noted on the first postoperative day), in 3 cases, or late (beyond 1 year from surgery), in 8 cases. We highlight that these were 2 distinct groups: early CTR decentrations versus late CTR decentrations. In the early cases, decentration was likely due to inappropriate selection of a capsular tension device at the time of surgery (i.e., standard CTR insufficient for degree of zonular instability) or further iatrogenic trauma to existing zonules. Despite what has been discussed in some circles, a sulcus-supported PCIOL is unlikely to be an appropriate choice in cases of zonular laxity as found in one case. In these situations, the surgeon must make the choice of scleral fixation of a CTR, the use of a CTS, scleral or iris fixation of a PCIOL, or use of an anterior chamber IOL. Each of these options has its own pros and cons, which are beyond the scope of this article. Late-onset spontaneous postoperative capsular bag decentration is a sequela of progressive zonular loss due to underlying pathology, particularly a concern in pseudoexfoliation syndrome.15 Mechanisms of progressive loss of capsular support after cataract surgery are multifactorial and include lens epithelial cell proliferation and capsular contraction, zonulysis from underlying conditions, including pseudoexfoliation syndrome and congenital conditions such as Marfan’s syndrome, and accidental or surgical trauma. In this study, pseudoexfoliation syndrome was implicated in 6 of 8 delayed-onset decentrations, which is consistent with earlier reports of delayed-onset in-the-bag IOL dislocations.15 In a postmortem study of PCIOL centration, eyes with pseudoexfoliation syndrome had IOL decentration greater than that of a group of normals.16 Histopathologically, lysosomal enzymes have been demonstrated within pseudoexfoliation material, indicating a proteolytic mechanism of zonular disintegration.17 In certain susceptible patients, this process is likely to continue and, without intervention, eventually may result in the loss of all zonular support and dislocation of the capsular bag. Delayed spontaneous dislocation of in-the-bag PCIOLs has been reported up to 5 to 10 years after uneventful surgery and has been described in pseudoexfoliation syndrome.15,18 –20 Jehan et al reported 8 eyes with pseudoexfoliation (5 had glaucoma) with previous uncomplicated phacoemulsification and endocapsular PCIOL implantation that developed late spontaneous dislocation 57 to 115 months after surgery.15 The authors suggest that CTR use in these cases may reduce the risk of delayed dislocation in pseudoexfoliation. Some surgeons also advocate the use of a CTR routinely in all pseudoexfoliation patients at the time of cataract surgery.21 Although the use of a CTR has been
Ahmed et al 䡠 Postoperative CTR Dislocations shown to improve IOL centration postoperatively,3–5 these are short-term studies. While, in principle, a CTR may have provided initial support, it is unknown if this would have prevented or delayed late-onset decentration in these progressive cases. Indeed, in our study of 11 patients, 7 of whom had pseudoexfoliation syndrome, postoperative PCIOL decentration occurred despite the use of a standard CTR, requiring intervention from 22 days to 6.3 years after initial implantation. Although the mean interval to displacement for lateonset CTR decentration was 49.6 months—a fair amount of time since initial implantation—this is shorter than the reported interval for delayed-onset PCIOL dislocation in pseudoexfoliation syndrome.15,19 This may be due to the presence of greater zonular instability in these more susceptible patients (necessitating CTR use in the first place). We were surprised to find that 2 cases of traumatic zonular damage, typically a nonprogressive condition, developed later-onset decentration. We suspect that they may have had initial extensive dialysis that may not have been suitable for a standard CTR. Delayed subluxation also may have been due to the fact that both of these patients were younger (⬍60 years) and perhaps at greater risk for lens epithelial cell proliferation and capsular contracture in an already compromised capsulozonular complex. It is also interesting to note that the placement of 2 CTRs within the bag in an attempt to provide additional support in one of these patients, as has been suggested by others,22 did not prevent late-onset decentration. Of the 9 patients with subluxation, 8 subluxed so inferiorly, thus indicating greater loss of superior zonular support and resultant decentration. Superior zonular support seems to be a critical factor in maintaining IOL centration, consistent with what was found in delayed spontaneous PCIOL dislocation in pseudoexfoliation, where Jehan et al found that 6 of 8 patients had inferior dislocation.15 We suspect that the superior zonules either are at greatest risk of damage, possibly related to gravity, or are affected preferentially in the disease process. It is also possible that they were more likely to be damaged at the time of the initial surgery, because most of these older cases were of phacoemulsification through a superior incision using a grooving technique that would have created the greatest stress subincisionally (superiorly). Most of the patients in our series were found to have a well-centered PCIOL within the capsular bag, with a centered continuous curvilinear capsulorrhexis (CCC). This would indicate that the CTR is very effective in redistributing and equalizing circumferential zonular tension around the capsular bag. However, when the remaining zonules are (or become) insufficient to provide adequate global support, the capsular bag itself is at risk of decentration. Centripetal capsular contraction—symmetric or asymmetric— of the CCC and continual traction on already weakened zonules may be associated with progressive zonular loss, IOL decentration, and capsular bag dehiscence.19,23,24 Although rarely found in can-opener–style capsulotomies, since the advent of the CCC it has become more frequent. Treating the capsular contracture with Nd:YAG laser radial anterior relaxing incisions has been found to be an effective
prevention against IOL dislocation.24 Contrary to the initial theory, CTRs do not necessarily prevent capsular contraction or phimosis; these are more likely to occur with a smaller size ring.25 Capsular contraction syndrome, which is more likely to occur with pseudoexfoliation, older age, weak zonules, and metaplastic proliferation of lens epithelial cells, has been reported to result in IOL decentration even in the presence of an endocapsular tension ring.26 –29 Neodymium:YAG laser anterior capsule relaxing incisions were performed to stabilize these cases. Although subjectively we found a greater amount of anterior capsular opacification than expected, none of the patients in our study had previous laser anterior capsulotomies. Preemptive early Nd: YAG laser treatment given to the contracting anterior capsule and CCC may be an appropriate preventative step in these cases. Unfortunately, other than assessing the degree of instability at the time of surgery and, perhaps, the degree of capsular contraction, there is likely little that surgeons can do to predict those patients who may go on to develop late spontaneous decentration. However, as has been suggested,30 we do feel that new-onset or worsening pseudophacodinesis in susceptible eyes may be a sign of impending decentration. The constant motion of the IOL/capsular bag in pseudophacodinesis may cause progressive shearing of existing zonules over time. In fact, in 2 cases in our series this was an indication for surgical intervention. In the future, the ultrasound biomicroscopy, which has been a useful tool in identifying focal areas of zonular loss,31,32 may be adapted to correlate zonular status with the future risk of decentration better. There is little in the published literature on the incidence of in-the-bag CTR dislocation and its management. In one case report, an ab externo suture repositioning was successfully performed for a dislocated CTR complex after severe coughing.10 In another case report, after CTR implantation in a child with Marfan’s syndrome the patient developed postoperative decentration requiring multiple revisions.11 Recent case reports have described removal techniques of a posterior dislocated CTR within the vitreous body due to intraoperative posterior capsule breakage.6 –9 Although CTR removal and IOL exchange is an option in these cases, removal may cause excessive tissue trauma and larger incisions, and explanation typically requires increased manipulations and complications. The exchange IOL would need an anterior chamber IOL or iris-fixated or scleral-sutured PCIOL—all of which have potential problems, especially in glaucoma patients. Principles of the repositioning of CTR decentrations are similar to those of surgical repositioning of displaced PCIOLs. Surgical technique, in terms of an anterior or posterior approach, should be based on whether the CTR–IOL– capsular bag complex is subluxed in the retropupillary/anterior vitreous space or dislocated into the posterior vitreous. For completely dislocated CTRs in the vitreous cavity, we suggest a PPV to free the CTR–IOL– capsular bag complex from the vitreous, with subsequent suturing of the CTR to the sclera. Although this requires temporary stabilization of the complex in the retropupillary space, the use of microforceps, capsule retractors, and creative needle passes makes this possible.
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Ophthalmology Volume 112, Number 10, October 2005 In the case of subluxed CTR–IOL– capsular bag complexes accessible via an anterior segment approach, scleral fixation of the complex with the use of polypropylene suture passes is an excellent method of recentration and support. We prefer the control and precision of the ab externo suturing technique. The presence of a CTR greatly facilitates capturing the capsular bag. Although there is the potential for capsular tearing and extension with needle passes made through a fresh capsule,33 we do not feel that this is a major issue with postoperative fibrotic and fused capsules. The CTS, which has emerged as a useful device and implant for the management of the dislocated crystalline lens, seems to provide an alternative to needle passage through the capsule in cases of IOL/CTR decentration as well. With reopening of the superior fornix of the capsular bag, the CTS can be suture fixated to the sclera. Considering that the need for superior capsular bag support was critical in the majority of postoperative IOL and CTR subluxations, most of the patients in our study had either direct fixation of the CTR or placement of a CTS to the superior sclera in these cases. We recommend the use of a higher tensile strength suture like 9-0 polypropylene, as opposed to 10-0 polypropylene, to prevent postoperative suture breakage. Our case series’ results show that it is possible to salvage the CTR–IOL– capsular bag complex with suture fixation. The majority of patients had improvements in VA with satisfactory centration after surgical repositioning, with minimal astigmatic error or significant IOL tilting. As our current study presents short- to medium-term results, further follow-up is required to determine long-term success, including issues of potential late-onset suture breakage. However, these patients often have concomitant pseudoexfoliative glaucoma, and in this series, 2 patients progressed with advanced glaucoma resulting in further visual loss, thus stressing the need for caution. Whether an advanced glaucoma disease state is related to the severity of zonular loss or whether the complexity of the surgical repositioning procedure is too great an insult for these compromised eyes is uncertain. We suggest careful preparation and postoperative monitoring in these eyes undergoing further surgery. In summary, postoperative subluxation or dislocation of a previously implanted CTR and IOL– capsular bag complex may occur due to inadequate underlying zonular support for a standard CTR or aggressive capsular contracture and/or progressive zonulysis. Capsular tension rings embody an attempt to maximize existing capsular bag support, but they do not halt the underlying metabolic or disease process in zonulysis. This seems to be of particular concern in pseudoexfoliation syndrome. To our knowledge, this is the first published series describing in-the-bag CTR decentration and its management with surgical repositioning. Based on our findings, one may question the value of CTR implantation at all in cases of zonular weakness. However, an alternative view may be that the CTR may have prevented intraoperative complications and delayed dislocation, and permitted surgical repositioning to be performed in some cases. The value of the CTR for intraoper-
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ative support in mild zonular weakness has been established. Although not completely preventative, the CTR seems to limit capsular contraction and asymmetric capsular bag and IOL displacement. Furthermore, in the event of postoperative decentration we feel that surgical repositioning is more easily accomplished in the presence of a CTR, which, acting as a backbone, may be directly sutured through the capsule to the sclera. We also know that there has been a large number of patients—the vast majority—in whom CTR implantation has maintained adequate centration. However, this may be due to the long interval to presentation and the fact that CTRs were introduced within the last 10 years. Clearly, at this time there are insufficient data to determine the true incidence of CTR decentration and the long-term benefit of CTR use in progressive cases of zonulysis. For these reasons, we encourage surgeons to consider the CTR—for both intraoperative and postoperative support—in cases of zonular weakness, but suggest using careful implantation techniques to prevent further zonular loss and caution in cases of more advanced zonulopathy, in which a sutured capsular tension device or alternative IOL fixation should be considered. Surgeons who employ the CTR must evaluate capsular bag stability intraoperatively and, if necessary, need to be facile in suturing techniques at the time of primary surgery should it be deemed that a standard CTR alone is insufficient. It is our opinion that simply inserting a second or even third CTR will not provide substantially extra support, as was found in one patient in this study. In these cases, either direct suturing of the standard CTR through the capsule31,34,35 or placement of modified CTR or CTS device(s) at the time of cataract surgery would be indicated. Multiple factors are likely involved in the prevention of capsular bag and IOL dislocation in patients with zonular weakness. These include a gentle zonule-friendly phacoemulsification technique, generous size capsulorrhexis, meticulous cortical cleanup and anterior capsule polishing, large CTR, use of an acrylic IOL (least anterior capsular opacification),36 –38 and intensive topical steroids and nonsteroidal antiinflammatory drugs postoperatively to treat inflammation. The importance of long-term postoperative observation for progressive zonulopathy must be stressed. Although these cases are relatively uncommon, they should be managed at the first signs of capsular contracture with early radial Nd:YAG laser anterior capsulotomy. At the first signs of instability, such as pseudophacodinesis, or progressive IOL decentration, surgical intervention should be considered to minimize the need for more invasive methods and/or vitrectomy. Certainly the CTR and its derivatives have been an exciting development in phacoemulsification of the complex cataract. Surgeons are still learning about the long-term implication of in-the-bag placement of a PCIOL and/or CTR in certain zonular conditions, particularly pseudoexfoliation. This study sheds some light on this issue and provides a surgical approach to manage decentered CTRs. Despite the theoretical advantages of a CTR in progressive zonulopathy like pseudoexfoliation syndrome, a standard
Ahmed et al 䡠 Postoperative CTR Dislocations CTR may not fully prevent late-onset dislocation. Further controlled studies are needed to assess the value of routine CTR placement in pseudoexfoliation syndrome, to select an appropriate capsular tension device, to assess the incidence of CTR decentration, and to select the proper approach to managing CTR subluxations or dislocations.
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