Purpose
To determine outcome of cataract surgery in severely subluxated traumatic cataracts.
Design
Noncomparative case series.
Methods
Retrospective review of cataract surgery in all consecutive eyes with at least 6 clock hours of zonulysis, for patient demographics, presenting best-corrected visual acuity (BCVA) and postoperative BCVA at various time points, extent of zonulysis, and type and timing of insertion of capsular tension device. Main outcome measures were retention of the capsular bag and BCVA at last visit. Secondary outcome measures included IOL stability and centration, and perioperative complications.
Results
There were 41 eyes (41 patients). Mean age at time of surgery was 57 years and the mean duration of follow-up was 21.4 months. The capsular bag was preserved with aid of a Cionni modified capsular tension ring (CTR) in 36 eyes (87.8%) and a combination of a capsular tension segment (CTS) and CTR in 2 eyes. In 3 eyes with total zonulysis, the bag could not be preserved despite the use of a CTS in 2 eyes. Preoperatively only 9 of the 41 eyes (22.0%) had a BCVA of 20/40 or better, as compared to 38 eyes at the last visit (92.7%, P < .001, χ 2 test). Posterior capsule rupture occurred in 3 eyes, 2 of which occurred during fixation of the CTR.
Conclusions
The capsular bag can be successfully preserved even in severely subluxated traumatic cataracts with the aid of fixated capsular tension devices.
Subluxated lenses are among the most challenging cases encountered by the cataract surgeon. They may be congenital, as in cases of Marfan syndrome and microspherophakia, or acquired, such as those attributable to trauma.
Capsular tension devices such as the capsular tension rings (CTR) or capsular tension segments (CTS) have been successfully used in the management of congenital subluxated lenses. However, in these young patients the vitreous gel is often still formed and the nucleus is soft and easily aspirated; hence extreme lens instability and vitreous encounter are relatively uncommon.
In cases of traumatic lens subluxation, the extent of zonular disruption can be extremely severe, with vitreous prolapse into the anterior chamber (AC). Furthermore, there may also be other concomitant issues that require surgical attention, such as raised intraocular pressure (IOP), iridodialysis, and/or traumatic mydriasis. In these cases, retention and stabilization of the capsular bag is often difficult. While CTRs have been successfully used in traumatic cataracts with less than 6 clock hours of zonulysis, a fixated capsular tension device such as a Cionni modified CTR (Morcher GmbH, Stuttgart, Germany; Type 1l or 2L) with eyelets for suturing to the sclera or a CTS with an eyelet (Ahmed capsular tension segment, Morcher GmbH, Stuttgart, Germany) may be required to ensure centration and stability of the capsular bag in eyes with greater extents of zonulysis. In some of these eyes, the lens may be too posteriorly displaced for an anterior approach, necessitating a pars plana route of removal. In this paper, we reviewed the role of capsular tension devices in preserving the capsular bag, both intraoperatively and postoperatively in severely subluxated traumatic cataracts, as well as the visual outcomes and complications of surgery.
Methods
We retrospectively reviewed the case records of all consecutive patients (starting from the first case) with traumatic subluxated cataracts, having at least 6 clock hours of zonular weakness or loss that had undergone cataract removal via an anterior approach by 1 surgeon (S.P.C.) at the Singapore National Eye Centre from September 1, 2001 to November 30, 2009. Data were collected on patient demographics; presenting best-corrected visual acuity (BCVA); IOP; density of the nucleus using the Lens Opacity Classification system III; operative technique; number of fixation points and type of capsular tension device used; BCVA at 4 weeks, 1 year, 2 years, and at the last visit; and complications including posterior capsule rupture (PCR), cystoid macular edema (CME), retinal detachment, and intraocular lens (IOL) decentration. A poor visual outcome was defined as a BCVA of worse than 20/40.
The extent of zonulysis was assessed based on the amount of displacement and/or tilt of the lens as well as its mobility intraoperatively. A single-point fixation capsular tension device was used when zonulysis of 6 to 8 clock hours was present and a double-point fixation capsular tension device was used when zonulysis of 9 to 12 clock hours was present.
Surgical Technique
These cases were done under general anesthesia unless there were contraindications, in which case a peribulbar block was used. Intravenous mannitol (Osmofundin 20%; B Braun Medical Industries Sdn Bhd, Penang, Malaysia) was given just prior to surgery if the eye had an unusually shallow AC or if vitreous was present in the AC. Following a 2.65-mm temporal clear corneal incision, a dispersive ophthalmic viscoelastic device (OVD) was injected to displace any vitreous in the AC as well as to tamponade the anterior vitreous face. In cases where the lens was displaced backwards into the anterior or mid vitreous, it was engaged and brought forward to the anatomic plane by gently piercing the anterior capsule with a 27-gauge needle. If there was significant lateral as well as posterior displacement, scleral indentation was performed to bring the lens into view prior to engaging it. The capsulorrhexis was then completed with 2 micro capsulorrhexis forceps to provide counter traction as required.
As the capsulorrhexis progressed, iris hooks were introduced to centralize and to support the capsular bag, ensuring that no excessive tension was placed on the edge of the capsulorrhexis, which may result in radial extensions of the capsulorrhexis. Thorough multiquadrant cortical cleaving hydrodissection was next performed, ensuring that the nucleus was able to rotate easily within the capsular bag. The OVD was then injected just under the anterior capsule to viscodissect the cortex from the capsular bag and to protect the posterior capsule in the area opposite the main incision, where most of the chopping maneuvers would be performed. The capsular tension device, with a double-arm 10/0 polypropylene suture (Prolene; Ethicon, New York, New York, USA) on straight needles pre-placed in the leading eyelet, was inserted just under the anterior capsule at this point in time, and then rotated until the eyelet was at the area of greatest zonular dehiscence. In order to minimize the stress on the residual zonules in these eyes with already extensive zonule loss, the effective radius of the modified CTR was reduced by compressing the ring between a Sinskey hook inserted into the leading placement hole and a Kelman McPherson forceps, which is used to hold onto the other end of the CTR, similar in concept to the fish tail technique described by Angunawela. An alternative method employed to reduce the stress on the zonules during the insertion of a modified CTR was to use a Sinskey hook to guide the distal portion of the device rather than allowing it to be pushed against the capsular bag. In cases where a Cionni 2L was used, the second eyelet was threaded with the Prolene suture just before its insertion into the eye. This minimizes the risk of the sutures becoming entangled. The sutures were left trailing out of the incision.
Phacoemulsification, using a chop technique where possible, was followed by cortex removal and injection of the IOL. A scleral flap was created either under direct visualization following conjunctival peritomy or by the dissection of a corneoscleral pocket. Where 2 eyelets had to be sutured, the sites of fixation were marked prior to the dissection as they were not always diametrically opposite one another, due to variations in capsular bag size. An ab externo technique similar to that described by Ahmed and Crandall was used for placement of the 10/0 Prolene suture 1.5 mm posterior to the limbus. In the case of the corneoscleral pockets, the suture was retrieved from within the pocket using a Sinskey hook. The suture ends were tied with a surgical knot after adjusting the tension of the sutures such that the IOL was centered. The OVD was removed from the AC and the capsular bag and, where safe, from behind the IOL. The incisions were rehydrated as necessary and checked for integrity. Throughout the entire procedure, whenever any instruments were withdrawn from the eye, the AC was maintained with an air bubble and/or OVD, as collapse of AC may result in further zonular stress and vitreous prolapse.
Where possible, any vitreous that had prolapsed into the AC was displaced as described above. If an anterior vitrectomy was required, this was performed as late as possible, using triamcinolone acetonide to better delineate the vitreous as required. Postoperatively, topical prednisolone acetate 1% and levofloxacin or moxifloxacin were commenced and were tapered off according to the amount of inflammation. The patients also received antiglaucoma medications as required.
The above is a description of our current technique. In the initial cases, insertion of the capsular tension device was delayed until after the nucleus had been removed, and the IOL was only inserted after fixation of the capsular tension device.
Outcome Measures
The main outcome measures were retention of the capsular bag and BCVA at 4 weeks, 1 year, 2 years, and last visit. Secondary outcome measures included IOL stability and centration and perioperative complications. Statistical analysis was performed using SPSS (Ver 13.0; SPSS Inc, Chicago, Illinois, USA). Univariate analysis of categorical data was performed using the χ 2 test.
Results
There were 41 eyes (41 patients) with severe traumatic lens subluxation that were surgically managed with the intention of implanting a capsular tension device. Their mean age at time of surgery was 57 years (standard deviation [SD] 11, range 30 to 80 years) and the mean duration of follow-up was 21.4 months (median 9.6 months, range 1-112 months). The majority were male (27 patients, 65.9%) and Chinese (34 patients, 82.9%).
The majority of eyes (27, 67.9%) had nuclear sclerosis of 2+ or less. Nineteen eyes (46.3%) had 6 to 8 hours of zonulysis and the remainder had at least 9 clock hours of zonulysis. The lens was decentered in 21 eyes and tilted in 12 eyes. In 8 eyes, there was severe phacodonesis without displacement on slit-lamp examination. Nineteen eyes had, in addition, other anterior segment abnormalities. These included iridodialysis in 2 eyes, sphincter rupture in 15 eyes, sphincter rupture with iridodialysis in 1 eye, and adherent leucoma in 1 eye.
The capsular bag could not be retained in 3 eyes with total zonular weakness. In 2 of these eyes the entire bag collapsed following removal of the cataract and could not be adequately inflated, and there was also insufficient zonular integrity to allow insertion of a CTR. In 1 of these 2 eyes a CTS had been placed prior to phacoemulsification and it was removed together with the bag. The IOL was scleral fixated in 1 eye and iris sutured in the other eye. In the third case, the CTS had to be removed following the occurrence of a PCR as described below, and the IOL was sutured to the iris. All these 3 eyes had good final BCVA with a follow-up period of 7 to 24 months. Of the 38 eyes where the capsular bag was retained, a single-point fixation capsular tension device was used in 16 eyes (42.1%) consisting of 14 eyes with a Cionni 1L and 2 eyes with a CTS in combination with a CTR. A 2-point fixation capsular tension device was used in 22 eyes (57.9%), comprising 6 eyes with a combination of a Cionni 1L and a CTS and 16 eyes with Cionni 2Ls.
Twenty-one of the 41 eyes (51.2%) had vitreous presentation before the start of surgery, of which 17 eyes required a vitrectomy. Four eyes that initially did not have vitreous in the AC required vitrectomy at the end of surgery. PCR occurred in 3 eyes. In one eye, the PCR occurred during phacoemulsification and the CTS had to be removed. The IOL was sutured to the iris. In the other two patients, PCR resulted from a puncture of the capsular bag by the 10/0 Prolene needle during the process of fixation. The PCR was small in one eye, and occurred before insertion of the IOL. A 3-piece IOL was then placed in the sulcus with posterior optic capture. In the other case, the IOL and Cionni 2L had already been placed in the capsular bag when the PCR occurred, resulting in a mildly decentered but stable IOL. All these 3 patients had 20/40 or better visual acuity at the last visit.
Preoperatively only 9 of the 41 eyes (22.0%) had a BCVA of 20/40 or better, as compared to 38 eyes at the last visit (92.7%, P < .001, χ 2 test). The causes of the poor vision at the last visit in the other 3 eyes were posterior capsule opacification (PCO) (1 eye), cone-rod dysfunction (1 eye), and pre-existing epiretinal membrane with recent-onset cystoid macular edema (1 eye). At 4 weeks, 36 eyes (87.8%) had a BCVA of 20/40 or better. In the 18 eyes that had at least one year of follow-up, the visual acuity at one year was 20/40 or better in 17 eyes (94.4%). There was no difference between the BCVA at 4 weeks and at one year in 15 of 18 eyes (83.3%), improvement by 2 Snellen lines in two eyes (11.1%; 20/40 to 20/25 and 20/60 to 20/40), and worsening by 2 Snellen lines in one eye (5.6%; from 20/20 to 20/30). Of the 13 eyes with at least two years of follow-up, all had good vision and there was no difference in the BCVA at one year and at two years ( Table ).
