Phacoemulsification of white cataracts presents a challenge to all cataract surgeons and can become complicated in the presence of a small pupil, shallow anterior chamber, and phacodonesis.1 However, recent advances in equipment and instrumentation, such as pupil expanders and capsule stabilization tools, enable the surgeon to perform cataract surgery uneventfully even in the case of a compromised zonule and complicated anatomical features.2 We describe the simultaneous use of 4 flexible iris hooks for dilation of the pupil and 4 iris hooks for stabilization of the capsular bag in a patient with a very deep set and small eye, narrow palpebral fissure, very small pupil, shallow anterior chamber, mature cataract, and a compromised zonule.
A 60-year-old white man was referred to our cataract clinic for routine cataract extraction in the left eye. The corrected distance visual acuity was 6/9 in the right eye and hand movement in the left eye. The intraocular pressure was 12 mm Hg bilaterally. Slitlamp examination showed quiescent pseudophakia in the right eye with a well-placed anterior chamber intraocular lens (AC IOL) and a small pupil. The IOL was implanted in a secondary procedure following a complicated cataract extraction. Biomicroscopy of the left eye showed a white cataract and a very small pupil with a shallow anterior chamber. No phacodonesis was noted preoperatively, possibly due to the poor mydriasis. Fundoscopy in the right eye was unremarkable; B-scan ultrasound in the left eye showed a flat retina.
The patient was scheduled for left eye phacoemulsification and foldable posterior chamber IOL implantation using anterior capsule staining to facilitate a continuous curvilinear capsulorhexis (CCC) and iris hooks to secure pupil dilation during surgery. The preferred method of anesthesia was topical tetracaine hydrochloride 0.5% and proxymetacaine hydrochloride 0.5% eyedrops. The preoperative optical coherence biometry (IOLMaster, Carl Zeiss Meditec AG) was precluded by a remarkable lens density. A-scan ultrasonography (820 ultrasonic biometer, Humphrey Division, Carl Zeiss Meditec AG) was performed, which confirmed the diagnosis of a shallow anterior chamber and a short eye with an axial length of 21.50 mm, an anterior chamber depth of 2.10 mm, and a lens thickness of 4.47 mm. Because of the risk factors for intraoperative capsule complications, the case was assigned to a high-volume cataract surgeon (G.C.).
Surgery was started by creating the main 2.75 mm clear corneal incision and 2 side ports. Four iris hooks (Synergetics, Inc.) were used as planned to secure maximum pupil dilation. During insertion of the hooks, the surgeon noted a marked dehiscence of the lens zonular fibers that could be triggered by the slightest lens touch (Video 1, available at: http://jcrsjournal.org). Trypan blue (Visionblue staining solution, Dutch Ophthalmic USA) was used to stain the anterior capsule, and the anterior chamber was filled with a cohesive ophthalmic viscosurgical device (Healon GV). The CCC was performed through the main corneal incision using a bent 30-gauge needle. To facilitate an anterior approach to lens removal, the capsular bag was stabilized using 4 additional iris hooks applied to the capsulorhexis edge prior to hydrodissection. The distal end of the iris hook was slightly bent by the surgeon to increase the hook’s angle and enable easier access to the capsule’s margin. Slight tension was applied carefully to the capsulorhexis margin by the iris hooks, pulling the capsule and lens complex.
Because of the marked brunescence of the nucleus and thick leathery posterior plaque, phacoemulsification was performed with the highest vacuum available (650 mm Hg) (Infinity, Alcon Laboratories, Inc.) to stabilize the lens during aspiration and enable the primary chop lens disassembling technique. Bottle height and aspiration rate were modified accordingly. To remove the last fragment, the phaco fluidics settings were lowered, given the increased risk for engaging the mobile and fragile posterior capsule. A 3-piece foldable acrylic IOL (MA60AC, Alcon Laboratories, Inc.) was implanted in the ciliary sulcus (Figure 1). The surgical procedure was concluded with an intracameral administration of acetylcholine (acetylcholine chloride intraocular solution 1:100 with electrolyte diluent) to induce miosis and 0.1 mL of cefuroxime 10 mg/mL for pseudophakic endophthalmitis prophylaxis in accordance to the European Society of Cataract and Refractive Surgeons study recommendations.
Postoperatively, the patient was started on topical prednisolone 1.0% and ketorolac 0.5% for 4 weeks; topical levofloxacin 0.3% 4 times daily for the first 2 weeks was used as postoperative endophthalmitis prophylaxis. The postoperative course was satisfactory with mild to moderate corneal edema lasting for the first 2 weeks. At the patient’s final follow-up appointment 6 weeks after surgery, the uncorrected distance visual acuity was 6/9 and the IOL was well-centered.
Several techniques for the removal of complicated cataracts with a compromised zonule have been described. These include intracapsular and extracapsular cataract extraction; anterior phacoemulsification with the use of a capsular tension ring (CTR)3; endocapsular lensectomy with vitrectomy and lens removal via the pars plana4; or the use of modified endocapsular rings such as the Cionni ring,5,6 Malyugin-Cionni ring, Ahmed segment (Morcher GmbH),7 capsular anchor,8 (Hanita Lenses), and Mackool capsule retractors (Microsurgical Technology).
The use of iris hooks to stabilize the anterior capsule was originally performed in patients with lens instability due to pseudoexfoliation syndrome.9 Also, phacoemulsification using iris hooks for the capsular bag is reported to be a good and safe method for removing subluxated cataractous lenses.10 A CTR can also be used to stabilize the capsular bag and facilitate in-the-bag implantation and optical centering in cases with partial zonular dialysis.11 However, a major disadvantage of inserting a CTR before phacoemulsification is that it subjects the capsular bag to radial stress forces that can cause the zonular dehiscence to extend; therefore, surgeons prefer to use CTRs for localized zonular dialysis. Because the etiology of lens dislocation was unknown in our case, concern arose about possible progressive zonular dialysis after the in-the-bag implantation of a CTR and subsequent in-the-bag IOL dislocation.12 Moreover, a fishtail CTR insertion technique can be used and has been described.13 Alternatively, one could have used capsule retractors (eg, MacKool)14; however, those were not available in our operating room at the time of surgery.
One advantage of using iris hooks is that most surgeons are familiar with their use for small pupils. Furthermore, capsule hooks in a shallow anterior chamber are much easier to use than a capsule anchor and other capsule stabilizing tools. To our knowledge, this is the first report in which the use of 4 iris hooks for pupil dilation was followed by simultaneous use of 4 hooks for capsular bag stabilization. Of course, extra care must be taken when placing the iris hooks as they can occasionally tear the margins of the capsulorhexis if placed carelessly. Also, the surgeon in our case chose not to grab the iris and capsule with the same hook because that would have affected his view and intraoperative intracapsular maneuvering.
The surgeon chose to perform cataract surgery under topical anesthesia because a local regional block in a small eye with a very shallow anterior chamber would have led to an even shallower anterior chamber from the increased retroocular pressure.15 We acknowledge that the choice of peribulbar anesthesia with meticulous preoperative ocular compression would also have been correct as it can result in a deeper anterior chamber for surgery. Using topical anesthesia inevitably had an impact on the choice of IOL implantation. The surgeon had decided against implantation in the bag with a Cionni segment16 or a capsule anchor8 because that would have required transscleral fixation in a scleral pocket, which can be difficult under topical anesthesia. Furthermore, transscleral fixation can often induce IOL tilting, especially when there is no capsule support, and given the relatively young age of the patient, there was a higher risk for long-term suture hydrolysis. Transscleral fixation is more complex and time consuming. As a result of these factors, the surgeon chose to implant the IOL in the sulcus. An AC IOL was not used as it would have narrowed the already narrow anterior chamber angle.
Finally, the use of phacoemulsification in contrast to extracapsular cataract extraction was justified in our case because microinvasive techniques in subluxated cataract surgery can result in a significant reduction in the complication rate and improved functional results. We think phacoemulsification with the aid of 4 iris hooks for pupil dilation and simultaneous use of 4 iris hooks for capsular bag stabilization is a safe and relatively easy technique for patients with a small pupil and a compromised zonule and can be considered an alternative to the use of a CTR.
What Was Known
- Complicated cataracts with a compromised zonule can be extracted with the help of special ophthalmic devices such as pupil expanders and capsule stabilization tools.
What This Paper Adds
- We describe the use of 4 iris hooks for pupil dilation and simultaneous use of 4 iris hooks for capsular bag stabilization in a patient with a small pupil and a compromised zonule.
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Video 1 Phacoemulsification using 8 flexible iris hooks in a patient with a short eye, small pupil, and phacodonesis. Note the marked phacodonesis that could be triggered by the slightest lens touch during insertion of the hooks.