Removal of a capsular tension ring from the anterior chamber angle

Removal of a capsular tension ring from the anterior chamber angle

techniques Removal of a capsular tension ring from the anterior chamber angle Brian C. Little, FRCS, FRCOphth, Theresa Richardson, FRCOphth, Sharon Mo...

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techniques Removal of a capsular tension ring from the anterior chamber angle Brian C. Little, FRCS, FRCOphth, Theresa Richardson, FRCOphth, Sharon Morris, MRCOphth, MRCSEd A 75-year-old woman presented with unexplained ocular hypertension 4 weeks after phacoemulsification. Steroid response was diagnosed initially until a misplaced capsular tension ring (CTR) was identified in the drainage angle. We describe the technique used to successfully remove the CTR from the drainage angle with minimal trauma. This case illustrates the importance of the initial surgical technique used for CTR insertion and emphasizes the role of gonioscopy in such a case. J Cataract Refract Surg 2004; 30:1832–1834  2004 ASCRS and ESCRS

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e describe our technique to remove a capsular tension ring (CTR) from the drainage angle with minimal trauma. The technique was used in a patient who had a misplaced CTR.

Case Report A 75-year-old woman with age-related cataract and no other eye disease had left eye phacoemulsification under peribulbar anesthesia. The surgery was complicated by what was thought to be rupture of the lens zonules in the inferotemporal quadrant between 3 o’clock and 7 o’clock. No vitreous prolapse was detected. A CTR (Morcher GmbH) was inserted using an injector and considered to be in position in the capsular bag. This was followed by endocapsular insertion of a foldable acrylic intraocular lens (IOL). The IOL appeared Accepted for publication January 23, 2004. From the Ophthalmology Department, Royal Free Hampstead NHS Trust (Little, Morris), London, and the Ophthalmology Department, Queen Mary’s Hospital (Richardson), Sidcup, United Kingdom. None of the authors has a proprietary or financial interest in any material or method mentioned. P. Moradi, MBBS, Senior House Officer, Ophthalmology Department, Queen Mary’s Hospital, Sidcup, United Kingdom, provided case report details. Reprint requests to Mr. B. Little, Ophthalmology Department, Royal Free Hampstead NHS Trust, Pond Street, London NW3 2QG, United Kingdom. E-mail: [email protected]  2004 ASCRS and ESCRS Published by Elsevier Inc.

satisfactorily centered at the end of the procedure, and the patient was discharged the same day on routine postoperative topical medication. The patient was reviewed 1 week later. The uncorrected visual acuity (UCVA) was 6/6 (Snellen acuity), and the IOL was well positioned with no anterior chamber (AC) activity. The intraocular pressure (IOP) was normal in both eyes. The patient was discharged on a routine course of tapered topical treatment. Three weeks later, the patient presented to the Accident & Emergency Department with a red, photophobic left eye. The UCVA was 6/9, and the eye showed mild diffuse conjunctival hyperemia with a few cells in the AC. The IOP was 24 mm Hg, and the IOL was minimally decentered inferiorly, with a small knuckle of vitreous visible in the AC. Postoperative iritis was diagnosed, and the patient was started on dexamethasone drops hourly and reviewed the following day. On review, the left eye IOP had risen to 30 mm Hg. This was attributed to steroid responsiveness, and a topical ␤-blocker was prescribed in addition to the steroid. The pressure and iritis had stabilized when the patient was reviewed 1 week later. At this visit, gonioscopy was performed. The CTR was identified seated in the iridocorneal angle against the trabecular meshwork with the 2 eyelets in the subincisional region at 1 o’clock. Because of the long-term risk for secondary mechanical iritis and glaucoma, it was decided to remove the CTR.

Surgical Technique Removal of the CTR was performed 8 weeks after the initial cataract surgery. A Sinskey hook and a pair 0886-3350/04/$–see front matter doi:10.1016/j.jcrs.2004.01.046

TECHNIQUES: LITTLE

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Figure 1. (Little) Gonioscopic examination of the CTR within the iridocorneal angle.

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of 19-gauge vitreoretinal (VR) forceps were used to remove the CTR. The steps of the technique were as follows: 1. Before surgery was started, the position of the CTR was confirmed gonioscopically and the location of the eyelets marked externally (Figure 1). The pupil was moderately dilated to confirm that the edge of capsule traversing the pupil was the free edge of a ruptured capsule and not the folded edge of a dehisced capsular fornix, as expected from the description of the initial surgery. Thus, an undiagnosed posterior capsule rupture had occurred during cataract surgery. 2. The original scleral tunnel was reopened at 12 o’clock, and 2 additional limbal stab incisions were made. The first incision was diametrically opposite the posi-

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tion of the CTR eyelets; the second was temporal and midway between the other 2 incisions. A bimanual anterior vitrectomy was performed to clear residual vitreous strands. The AC was filled with a sodium hyaluronate ophthalmic viscosurgical device (OVD). A Sinskey hook was inserted via the inferior incision, and the nasal end of the CTR was engaged in the angle (without direct visualization) and pulled centrally. The VR forceps were introduced via the scleral tunnel and used to grasp the body of the CTR when it became accessible. The CTR was stable in the jaws of the forceps, so the Sinskey hook was withdrawn from the eye and reintroduced via the temporal incision and engaged in the eyelet of the CTR (Figure 2). The end of the CTR was withdrawn from the eye using traction from the Sinskey hook and guidance from the forceps (Figure 3). Once externalized, the end of the CTR was held with a suture-tying forceps and dialed out of the eye. The CTR was extracted without resistance, internal hemorrhage, or iris trauma. Residual OVD was removed from the eye, and subconjunctival steroid and antibiotic were administered.

Discussion The first use of an endocapsular ring to support weak or absent lens zonules was described by Hara and

Figure 2. (Little) A VR forceps holds the CTR, and a Sinskey hook

Figure 3. (Little) The CTR is withdrawn through the side incision

is placed within the eyelet.

using the Sinskey hook.

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TECHNIQUES: LITTLE

Figure 4. (Little) Ultrasound B-scan shows the CTR displaced in the iridocorneal angle.

coauthors in 1991.1 Capsular tension rings are available in a variety of designs and have proved useful in compensating for rupture or absent lens zonules and ensuring that the IOL can be implanted in the bag and remain well centered. Available CTRs include the popular design used in this case, which comprises an open ring with 2 eyelets and has been produced by Morcher since 1993. Capsular tension rings work on the principle of expanding under elastic recoil to evenly distribute radial tension around the capsular bag equator. They maintain their circular shape and relieve localized tension in vulnerable areas. The CTR’s resistance to compression reduces local distortion of the bag by centrally directed radial traction during surgery, thus reducing localized zonular stress. Additionally, a floppy posterior capsule is placed under tension and is effectively “drum-skinned,” which may reduce the risk for aspiration and rupture. Although CTRs are fairly easily inserted into the capsular bag, complications include progression of a capsule tear and posterior dislocation of the CTR. Zonular dialysis extension, capsule perforation during insertion, and even complete posterior dislocation of the capsule with the CTR have been reported.2 To our knowledge, there have been no reports of AC misplacement. Capsular tension rings can be introduced before or after the nucleus is removed. If the nucleus has been removed, the capsular bag should be well expanded with an OVD before CTR insertion to avoid the leading end of the ring catching in the equatorial fornix of the bag. This produces characteristic tension folds across

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the posterior capsule. If additional force is applied, the ring can rupture through the capsule into the vitreous or be deflected forward out of the bag and into the AC. This can go unnoticed, particularly in an eye with a well-dilated pupil and when the natural focus of the surgeon is on the entry point of the ring into the bag. With a steep angle of approach on insertion, the distal end of the ring is more likely to come straight out of the bag on the opposite side than with an angle of approach that is parallel to the iris plane. In our case, if the CTR had not been misplaced into the AC, the ring would likely have ended up in the vitreous because of the undiagnosed posterior capsule break. This case highlights the importance of gonioscopy. If a case in which a CTR has been used presents with delayed postoperative ocular hypertension and mild iritis, surgeons should consider that the CTR may have been displaced into the AC. This can be confirmed gonioscopically or, if no clear view is possible, by B-scan ultrasound (Figure 4). The technique we used for CTR removal proved to be safe and effective and resulted in resolution of the iritis and ocular hypertension. Although Ma and coauthors3 recently described a technique to remove a CTR posteriorly displaced in the vitreous from an enlarged sclerostomy site, this is the first case describing a surgical technique for removing a CTR from the AC. Our case highlights an important and unusual complication of CTR use. With increasing popularity of rings and the reported use of multiple rings for prevention of capsule contraction syndrome,4 we may see more of this problem in the future.

References 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; 22:358–359 2. Menapace R, Findl O, Georgopoulos M, et al. The capsular tension ring: designs, applications, and techniques. J Cataract Refract Surg 2000; 26:898–912 3. Ma PE, Kaur H, Petrovic V, Hay D. Technique for removal of a capsular tension ring from the vitreous. Ophthalmology 2003; 110:1142–1144 4. Liu CSC, Eleftheriadis H. Multiple capsular tension rings for the prevention of capsular contraction syndrome [letter]. J Cataract Refract Surg 2001; 27:342– 343

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