Anatomic evaluation of the Morcher capsular tension ring by ultrasound biomicroscopy

Anatomic evaluation of the Morcher capsular tension ring by ultrasound biomicroscopy

J CATARACT REFRACT SURG - VOL 32, MAY 2006 Anatomic evaluation of the Morcher capsular tension ring by ultrasound biomicroscopy Jeffrey A. Boomer, MD...

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J CATARACT REFRACT SURG - VOL 32, MAY 2006

Anatomic evaluation of the Morcher capsular tension ring by ultrasound biomicroscopy Jeffrey A. Boomer, MD, David W. Jackson, MD

PURPOSE: To analyze the anatomic position of the Morcher capsular tension ring (CTR) by anterior segment ultrasound biomicroscopy. SETTING: Academic institution. METHODS: Fourteen pseudophakic eyes (13 patients) with placement of a Morcher CTR during cataract extraction had ultrasound biomicroscopy. RESULTS: In all eyes, the CTR had a position between the intraocular lens haptics and the ciliary body without posterior iris touch. CONCLUSIONS: In this small population of eyes, the Morcher CTR was found to be in a consistent, safe, and stable location in the capsular bag. J Cataract Refract Surg 2006; 32:846–848 Q 2006 ASCRS and ESCRS

The capsular tension ring (CTR) is a relatively new tool available for complicated cataract surgeries. It was originally designed in 1990 by Nagamoto and Bissen-Miyajima,1 who demonstrated its ability to support the capsular bag in cadaver eyes. In 1993, Legler and Witschel2 developed the first CTR to be used in humans. The CTR was first commercially available from Morcher and later by Ophtec. The Morcher CTR was U.S. Food and Drug Administration approved for use in 2004 and remains the only CTR available in the U.S. It is an open circular poly(methyl methacrylate) ring filament with eyelets at both free ends. Insertion of the CTR usually precedes or follows hydrodissection. The CTR has proved to be a valuable tool for managing cataract cases complicated by zonular dehiscence (traumatic or iatrogenic), zonular weakness (pseudoexfoliation syndrome), or ectopia lentis (idiopathic, Marfan’s, WeillMarchesani syndrome).3–9 It has also been shown in most

Accepted for publication November 10, 2005. From the Dean A. McGee Eye Institute, Department of Ophthalmology, University of Oklahoma School of Medicine, Oklahoma City, Oklahoma, USA. Supported in part by an unrestricted grant from Research to Prevent Blindness, New York, New York, USA. Reprint requests to David W. Jackson, Dean A. McGee Eye Institute, University of Oklahoma School of Medicine, 608 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73104, USA. E-mail: [email protected] Q 2006 ASCRS and ESCRS Published by Elsevier Inc.

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accounts to limit capsular bag phimosis, thus preventing intraocular lens (IOL) decentration, tilting, and deformation.10 The goal of this study was to gain a better understanding of the anatomic relationship of the Morcher CTR to posterior segment structures (ie, posterior iris, ciliary body) and the posterior chamber IOL using ultrasound biomicroscopy. PATIENTS AND METHODS After institutional review board approval was granted, the charts of 13 patients having placement of a Morcher CTR (type 14A, 14.5 mm diameter, compressible to 12.0 mm) during cataract surgery from February to October 2004 were retrospectively reviewed. Clinical findings and demographic and preoperative and postoperative data were collected. During postoperative visits, patients gave written informed consent prior to having ultrasound biomicroscopy. One control patient that had routine, uneventful cataract surgery without a CTR was included. Anterior segment ultrasound biomicroscopy was performed using the high-resolution B-scan mode with the I3 System-ABD (Innovative Imaging Inc.) by the same ultrasonographer using identical technique. A 20 MHz probe was used, providing 75 mm axial and 90 mm lateral resolution and a tissue penetration depth of 12 mm with an image width of 10 mm. A water-filled cover membrane was placed over the probe prior to applanation of the ocular surface, which was lubricated with artificial tears. The probe was placed perpendicular to the structures being scanned to produce axial cross-sections. The weight of the probe represented the applanation pressure. The positions of the Morcher CTR, optic, haptics, ciliary body, and iris were then determined by the investigators. All ultrasound 0886-3350/06/$-see front matter doi:10.1016/j.jcrs.2006.02.009

MORCHER CAPSULAR TENSION RING EVALUATION

biomicroscopies were performed between 3 weeks and 8 months after surgery. RESULTS

The case demographics, preoperative biometry, and etiology of zonular instability of the 13 patients are summarized in Table 1. The study included 6 women and 8 men (mean age 68 years; range 48 to 82 years). Axial lengths ranged from 21.90 to 25.57 mm (mean 22.04 mm). The mean horizontal white-to-white measurement was 12.2 mm, and mean anterior chamber depth was 3.24 mm. The etiology of the zonular instability was unknown in the majority of cases, except for in 3 eyes with pseudoexfoliation, 3 eyes with a history of trauma, and 1 eye with previous vitreoretinal surgery. Phacodonesis was documented preoperatively in 10 eyes and discovered intraoperatively in 6 eyes. All patients had a Morcher CTR type 14A placed in the capsular bag before or after hydrodissection/hydrodelineation by the same surgeon (D.W.J.), either manually or with an injector. A single-piece acrylic IOL (AcrySof SA60AT or SN60AT, Alcon Surgical Inc.) was placed in the capsular bag in all eyes. Cataract extraction was by phacoemulsification with temporal clear corneal incisions. No intraoperative or postoperative complications occurred. All ultrasound biomicroscopies demonstrated that the CTR and IOL remained in the capsular bag. The CTR sat between the IOL haptics and ciliary body, without posterior iris touch in all eyes (Figure 1). All IOLs remained centered in the capsular bag. Figure 2 is a control ultrasound biomicroscopy in a patient with the same IOL without a CTR.

Figure 1. Ultrasound biomicroscopy showing the position of the CTR between the IOL haptic and the ciliary body.

DISCUSSION

To our understanding, the intraocular position of a CTR has not been described using anterior segment

Figure 2. Control ultrasound biomicroscopy showing optic and haptic positions in an eye without a CTR.

Table 1. Case demographics, preoperative biometry, and etiology of zonular instability.

Case 1 2 3 4 5 6 7 8 9 10 11 12 13

Age (Y)

Sex

AL (mm)

HWTW (mm)

ACD (mm)

Etiology of Zonular Instability

82 76 53 66 52 76 69 48 75 77 74 76 61

F M M M M F F M F M M M F

21.90 23.11 23.10 22.65 25.05 23.84 24.40 24.89 25.57 23.52/23.59 22.90 22.90 23.25

11.5 12.5 12.5 12.0 12.0 12.0 12.0 12.5 12.5 12.5/12.5 12.5 12.0 12.0

2.25 3.16 3.88 3.83 4.40 3.78 3.83 3.83 3.06 2.11/2.82 2.68 2.44 3.26

Idiopathic Pseudoexfoliation Idiopathic Idiopathic Traumatic Idiopathic Idiopathic Traumatic CRVO/prior vitrectomy Bilateral/pseudoexfoliation Idiopathic Traumatic Idiopathic

ACD Z anterior chamber depth (I3 System-ABD Biometric A-scan mode); AL Z axial length; CRVO Z central retinal vein occlusion; HWTW Z horizontal white-to-white

J CATARACT REFRACT SURG - VOL 32, MAY 2006

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MORCHER CAPSULAR TENSION RING EVALUATION

ultrasound biomicroscopy. Despite a small patient population, this study demonstrated that the position of the Morcher CTR was consistent in all eyes, in spite of a wide range of axial lengths, anterior segment dimensions, and follow-up times. There were no cases of CTR–IOL contact with the iris pigment epithelium, which would theoretically lower the risk for uveitis–glaucoma–hyphema syndrome in these patients. The CTR stabilized the zonular apparatus–IOL in these eyes with zonular instability, which may alter effective lens position and refractive outcome. Further investigation to identify such an effect will be pursued.

REFERENCES 1. Nagamoto T, Bissen-Miyajima H. A ring to support the capsular bag after continuous curvilinear capsulorhexis. J Cataract Refract Surg 1994; 20:417–420 2. Legler UFC, Witschel BM. The capsular ring: a new device for complicated cataract surgery. Ger J Ophthalmol 1994; 3:265

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3. 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; 29:315–321 4. Cionni RJ, Osher RH, Marques DMV, et al. Modified capsular tension ring for patients with congenital loss of zonular support. J Cataract Refract Surg 2003; 29:1668–1673 5. Bayraktar S, Altan T, Ku¨c¸u¨ksu¨mer Y, Yılmaz O¨F. 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; 27:1620–1628 6. Cionni RJ, Osher RH. Endocapsular ring approach to the subluxed cataractous lens. J Cataract Refract Surg 1995; 21:245–249 7. Groessl SA, Anderson CJ. Capsular tension ring in a patient with Weill-Marchesani syndrome. J Cataract Refract Surg 1998; 24: 1164–1165 8. Menapace R, Findl O, Georgopoulos M, et al. The capsular tension ring: designs, applications, and techniques. J Cataract Refract Surg 2000; 26:898–912 9. Gimbel HV, Sun R. Clinical applications of capsular tension rings in cataract surgery. Ophthalmic Surg Lasers 2002; 33:44–53 10. Lee D-H, Shin S-C, Joo C-K. Effect of a capsular tension ring on intraocular lens decentration and tilting after cataract surgery. J Cataract Refract Surg 2002; 28:843–846

J CATARACT REFRACT SURG - VOL 32, MAY 2006