Posterior chamber implantation of a toric intraocular lens (IOL) offers a predictable and stable option to correct visually significant keratometric astigmatism.1,2 Effective astigmatism correction is dependent on aligning the IOL cylinder axis along the steep corneal meridian.3 However, spontaneous rotation of the IOL in the capsular bag is a potential complication that typically occurs early in the postoperative period.4 Risk factors include myopia, a history of ocular trauma, pseudoexfoliation, uveitis syndromes, capsulorhexis size, and IOL design and material.5,6 In cases in which the toric IOL is not aligned on the desired axis, the resulting astigmatism may be corrected with glasses or contact lenses (although often not desirable to patients who opted for surgical correction of astigmatism), limbal relaxing incisions (LRIs), or laser vision correction or the IOL can be repositioned surgically.
Techniques to suture a toric IOL in the absence of a capsular bag or within the bag for refixation of a dislocated IOL–capsular bag complex have been described.5,7,8 We describe a through-the-bag transscleral suture fixation technique to manage recurrent rotation of a hydrophilic acrylic toric IOL with a double-loop haptic design.
The toric IOL that was used (T-flex model 623T, Rayner Intraocular Lenses Ltd.) has a double-loop design; the inner and outer haptics are joined together, forming a loop with 2 angulations. The sutures are to be placed in the proximal and distal angulations of the haptic loop to achieve opposing bidirectional torque vectors and thus prevent clockwise or counterclockwise rotation of the IOL (Figure 1).
Tetracaine 0.5% is instilled in the eye. With the patient sitting up with both eyes focusing on a distant target, the axis positions 0 degree, 90 degrees, and 180 degrees are marked on the eye using a sterile axis marking system (Mastel Precision Surgical Instruments, Inc.). Mild intravenous analgesia and sedation are administered. The eye is prepped and draped in the usual sterile fashion.
With the patient supine and after placement of the lid speculum, the desired axis is marked with ink using the axis marking system. Two paracenteses, 1 superior and 1 inferior, are created. The anterior chamber is then inflated with a dispersive and cohesive ophthalmic viscosurgical device (OVD) using the soft-shell technique described by Arshinoff.9 A Kuglen hook is used to retract the iris and fully visualize the position of the entire IOL. The edge of the capsulorhexis overlying the optic is grasped with an Ahmed micrograsper (Microsurgical Technology) and lifted, allowing a cohesive OVD to be injected into the capsular bag. The IOL is then carefully freed from adhesion to the capsule using Sinskey and Kuglen hooks. The IOL is dialed in the capsular bag to the desired axis alignment. A conjunctival peritomy is then performed using Westcott scissors in the area of anticipated suturing of the IOL. Hemostasis is achieved using bipolar cautery. The location of the planned suture fixation is marked on the sclera with ink. Extra limbal paracenteses are made through which iris retractors (Grieshaber) are placed to allow visualization of the entire superior haptic (Figure 2, A).
At the planned suture-anchoring site, a partial-thickness scleral scratch incision is fashioned 1.5 mm posterior to the limbus using a tri-facet diamond blade (Figure 2, B). A 26-gauge hypodermic needle bent at the hub enters the eye perpendicularly in the scleral groove. The needle is passed under the superior haptic and through both the anterior and posterior capsular bag leaflets in the loop of the haptic. Ahmed micrograspers are used to hold the capsulorhexis edge to support the IOL and apply counterforce during needle passage (Figure 2, C).
One of the 2 curved needles on a double-armed 9-0 polypropylene suture (Ethicon, Inc.) is passed through a paracentesis into the barrel of the 26-gauge needle using a docking technique (Figure 2, D). The needle is then retracted out of the eye, thus externalizing the suture. Adjacent to the previous entry site, the 26-gauge needle is passed through the scleral groove again, but this time it is directed into the sulcus and above the entire IOL–capsular bag complex. The needle from the other end of the same polypropylene suture is docked into the 26-gauge needle and externalized in the same manner. As a result, the suture forms a loop through the proximal angulation of the haptic. Using Hoffman/Ahmed microscissors (Microsurgical Technology), a 1.0 mm relaxing incision is made in the capsulorhexis to minimize tension on the capsular bag from the suture loop (Figure 2, E). After both curved needles on the suture are cut off, a slipknot is tied to allow tension adjustment later (Figure 2, F).
A similar technique is used to pass another double-armed 9-0 polypropylene suture, this time through the distal angulation of the loop in the superior haptic, and secure it to the sclera with slipknots (Figure 2, G). The IOL position is then finalized with a Sinskey hook and by adjusting tension on both slipknots to ensure centration of the IOL in the bag without tilt and stable orientation at the 100-degree axis. When the IOL position is satisfactory, the sutures are locked and the knots buried in the sclera grooves (Figure 2, H).
All OVD is removed from the eye. No vitrectomy is required. Hydration is used to close all the incisions (Video 1, available at: http://jcrsjournal.org).
The transscleral suture fixation technique was performed in a 64-year-old man with visually significant cataracts and high corneal astigmatism who presented to our clinic for cataract extraction in the left eye. He had had unremarkable cataract surgery in the right eye. The baseline Snellen uncorrected distance visual acuity (UDVA) in the left eye was 20/200, and the corrected distance visual acuity (CDVA) was 20/30. The manifest refraction was −4.00 +7.00 × 98. On examination, a mildly nuclear sclerotic and posterior subcapsular cataract was noted. Optical biometry (IOLMaster, Carl Zeiss Meditec AG) measured an axial length (AL) of 24.12 mm, anterior chamber depth of 3.21 mm, and keratometry readings of 41.56 @ 11 and 46.68 @ 101. The corneal topography with an optical path difference scan (OPD-Scan III, Nidek Co., Ltd.) showed 41.62 @ 14 and 46.30 @ 104.
Because of the high degree of corneal astigmatism (cylinder of 5.12 diopters [D] from optical biometry), the option of a toric IOL was discussed with the patient, who wished to proceed with this. The patient’s data were sent to the manufacturer for IOL calculation. A T-flex toric IOL with a sphere of +16.0 D and cylinder of +7.0 D to be aligned on the 100-degree axis was selected and ordered. This IOL is hydrophilic acrylic with a double-loop design. The postoperative refraction was predicted to be −0.80 +0.10 × 100.
Uneventful cataract removal and in-the-bag implantation of the selected toric IOL in the left eye were performed, with the IOL aligned at 100 degrees as planned. There was complete 360-degree capsulorhexis overlap on the IOL optic. The OVD was removed from behind the IOL and from the anterior chamber at the conclusion of the case. One week postoperatively, high residual astigmatism was seen in the left eye (UDVA 20/200, CDVA 20/30 with manifest refraction −3.00 +6.00 × 87). The IOL was aligned on the 150-degree axis instead of on the desired 100-degree axis.
The options of corneal arcuate relaxing incisions, laser vision correction, or IOL repositioning were explained to the patient, and it was decided to proceed with IOL repositioning in the left eye. After the capsular bag was reopened, the IOL was dialed back to the desired axis of 100 degrees via 2 limbal side-port incisions in the operating room. The OVD was removed from behind the IOL and from the anterior chamber.
Within a month following the repositioning, the IOL rotated again to the 165-degree axis, with a manifest refraction of −4.50 +7.50 × 83; the UDVA and CDVA were unchanged. Given the unusual recurrence of spontaneous rotation, options of IOL repositioning with transscleral suture fixation (to prevent further rotation) versus IOL exchange were reviewed with the patient. An IOL repositioning with reverse optic capture to stabilize the IOL alignment was also considered, but this was not thought to be an effective option with this particular IOL design. The patient agreed to IOL repositioning with through-the-bag transscleral fixation.
The postoperative course was uneventful. At 11 months, the IOL alignment remained stable at the axis position of 100 degrees with minimal total astigmatism (Figures 3 and 4). The UDVA was 20/40 and CDVA was 20/20 with a manifest refraction −1.25 +0.50 × 13. The patient was satisfied with the visual outcome.
Toric IOLs are an important option in cataract surgery patients with significant astigmatism. Accurate centration and stable alignment of the toric IOL are paramount to desirable refractive outcomes. Large spontaneous rotation of the toric IOL is uncommon. The incidence of postoperative IOL rotation of more than 10 degrees is reported as between 0% and 14% within 2 months to 2 years10–13 and as 7.4% for the Rayner toric IOL specifically.14
Several mechanisms may contribute to spontaneous IOL rotation in the capsular bag. Rotation can occur early in the postoperative period prior to fusion of the IOL haptics and capsule (eg, due to retained OVD in the capsular bag).15,16 Mismatch between the IOL size and the capsular bag, especially in eyes with long ALs, may also contribute to this phenomenon.13 We suspect this was the most likely mechanism in our patient. Instability of the anterior chamber due to postoperative fluctuations of intraocular pressure (IOP) (eg, from residual OVD), pseudoexfoliation, or zonular weakness in the absence of other pathology or trauma can also contribute to IOL instability.13,17 These were not contributory factors in our patient as all OVD was removed at the end of the initial surgeries and no zonular or IOP issues were noted preoperatively or postoperatively.
The IOL material and design may play a role in spontaneous rotation.13,15 Acrylic material has a stronger tendency to adhere to the capsule than silicone.10,11 The Rayner toric IOL is made of a hydrophilic acrylic copolymer, with the mean rotation reported to be 3.44 degrees (range 0 to 12 degrees) 4 months postoperatively.3 Intraocular lens rotation may also occur as a result of capsular bag shrinkage from fibrosis, causing compression against the IOL haptics, although this is more often noted to occur late postoperatively.11 Capsule contraction has been noted to be more extensive in diabetic patients,18 although this was not present in our patient despite his being diabetic.
In cases of spontaneous toric IOL rotation, corneal incisions or LRIs, laser vision correction, or IOL repositioning are possible interventions when indicated. In our case, because of the high degree of residual cylinder, IOL repositioning was thought to be the better option. An initial attempt to reposition the IOL with rotation did not prevent recurrence of spontaneous IOL rotation.
Theoretically, by expanding the capsular diameter, a capsular tension ring (CTR) might enhance anterior and posterior capsule pressure on the IOL to enhance adhesion and prevent rotation. Our patient did not receive a CTR.
In our case, several factors were taken into account preoperatively and intraoperatively to prevent IOL tilt in the capsular bag. The principal factor in achieving a planar IOL position was the presence of good zonular support in the patient. Special care was taken to avoid zonular disruption during surgery. Moreover, each suture was anchored at the same distance posterior to the limbus (1.5 mm) to ensure equal oppositional forces on the same plane. Postoperatively, ultrasound biomicroscopy imaging (Figure 4, B) confirmed no significant tilt of the IOL in the capsular bag.
A capsule tear from suture tension is a potential complication of through-the-bag suture fixation. However, this is more likely a concern in a fresh capsule, which can be soft and fragile during cataract surgery. Capsule fibrosis occurs within weeks to months after IOL implantation.19 In settings of a fibrosed, more rigid capsule, as in our case, the risk for a capsule tear with suture fixation is likely lower. To reduce suture tension on the capsule, relaxing incisions were made within the capsule (Figure 2, E).
Suture fixation of a subluxated IOL–bag complex to the sclera has been reported.20–22 Specifically for toric IOLs, similar transscleral suture techniques have been described, but for different indications and not in the manner that we describe. Borkenstein et al.7 report scleral suture fixation of a Rayner toric IOL in an aphakic eye with lack of capsule support. McGrath and Lee5 describe a scleral fixation technique around both open-loop haptics of a supplementary sulcus toric IOL outside the capsular bag. Emanuel et al.8 report in-the-bag suture fixation of a toric IOL with open-loop haptics in settings of a dislocated IOL due to compromised zonular support. Our technique is novel in that this was not an aphakic eye nor was the IOL sutured because of a dislocated capsular bag. The in-the-bag toric IOL was sutured through the capsule to prevent IOL rotation. We took advantage of the unique double-loop haptic design to pass 2 sutures through both proximal and distal angulations of 1 haptic; in this way, 2 opposing vector forces would prevent clockwise and counterclockwise rotation of the IOL in the capsular bag. We are not aware of previous descriptions in which the surgeon had to suture the IOL in the bag to prevent recurrent rotation.
Our technique is applicable to fixation of other IOL designs in the absence of double-loop haptics. For instance, fixating sutures could be passed in a similar fashion through the fabric of a haptic (as in an IOL with open-loop haptics) to apply opposing vector forces, thus preventing rotation.
What Was Known
- Transscleral suture fixation of a toric IOL has been described in aphakic and pseudophakic eyes or for dislocated IOL–capsular bag complexes.
What This Paper Adds
- The technique we describe to manage recurrent postoperative toric IOL rotation uses transscleral and transcapsular suture passage through the haptics in 2 opposing directions to prevent IOL movement.
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Video 1 Intraoperative technique detailing transscleral suture fixation of the toric IOL through the capsular bag.