EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/194331
70 EW GLAUCOMA October 2011 February 2013 Advanced techniques for complex cataracts S by Tony Realini, MD Pseudoexfoliation mall pupils. Subluxed lenses. Or, in eyes with pseudoexfoliation, perhaps both at the same time. Complex cataract surgery has a higher risk of complications and requires skills beyond those necessary for more routine cases. At the 5th World Glaucoma Congress in Vancouver, British Columbia, a panel of expert surgeons shared a series of clinical pearls for dealing with challenging cataract cases. Small pupils Ike Ahmed, MD, Toronto, had several tips for dealing with a small pupil. "Intracameral phenylephrine is a good first step and will dilate some pupils without the need for any further interventions," he said. If there are posterior synechiae binding the iris to the anterior lens capsule, "a Kuglen hook can be used to perform synechiolysis," he said. "If there is a pupillary membrane present, the hook can also be used for stripping the membrane." If after these maneuvers the pupil remains too small to proceed with the case, "viscodilation with Healon5 [Abbott Medical Optics, Santa Ana, Calif.] can be effective," he added. Intracameral phenylephrine is a good first step for dealing with small pupils. Source: Ramon Lorente, MD If these conservative measures fail to achieve adequate pupil size, devices to mechanically expand the pupil may be needed. "Iris retractors are useful," said Dr. Ahmed. "The disadvantage is that they require additional incisions to place, but the advantage is that they can be left in until after removal of the viscoelastic at the end of the case." Con- New Orleans fun facts When states had their own currency, the Louisiana Dix (French for 10) was a favored currency for trade. English speakers called them Dixies and coined the term Dixieland. versely, pupillary expansion rings— such as the Malyugin ring—require no additional incisions but must be removed before removal of the viscoelastic, he said. "The Malyugin ring can be removed elegantly using the implantation device," he added. Zonular weakness There are several devices to help support the capsule when the zonules fail to provide adequate support for cataract surgery. Simple capsular tension rings and segments are designed to stabilize and center the capsule. Modified capsular tension rings and segments have eyelets to be engaged by iris hooks for additional axial support, which can also be utilized for temporary or permanent fixation, usually under a partial thickness scleral flap. "They are most easily inserted after the capsule has been inflated with a cohesive ocular viscoelastic device," said Dr. Ahmed, noting that the capsule can safely be stretched to approximately 1.5 times its normal size during inflation. In cases of frank loss of zonular support, lens subluxation may be present. "In these cases," said Dr. Ahmed, "I first place a modified CTS in the area of zonular loss and suture it in place under a scleral flap to stabilize the capsule in the anteriorposterior axis. Then I inject a CTR for circumferential support during the case." Eyes with pseudoexfoliation syndrome often present a constellation of challenges to the cataract surgeon, including small, poorly dilating pupils and zonular weakness. Optimizing surgical outcomes in these eyes starts in the preoperative period, said Paul Harasymowycz, MD, Montreal. "The first step is to be sure we recognize the signs of pseudoexfoliation so we can take the proper precautions. Also, we should take this opportunity to prepare the patient for the higher likelihood of complications," he said. Accommodating IOLs should be avoided in these eyes, as the capsular bag may not be stable postoperatively, he said. Also, it is worth considering an IOL with a larger optic than usual, as surgeons can minimize the risk of postoperative anterior capsular phimosis by crafting a larger than usual capsulorhexis. Pupil expansion can be accomplished using any or several of the options described above. "When addressing the nucleus," said Dr. Harasymowycz, "consider sculpting rather than chopping, and use higher phaco power than you otherwise might. Also, when cracking the nucleus, separate the two halves without any downward pressure." If there is capsular instability, all of the techniques described above are appropriate for eyes with pseudoexfoliation. "In addition, you can use an iris hook to capture and secure the anterior edge of the capsulorhexis as a pseudozonule," he suggested. He advised using nonsteroidal anti-inflammatory agents preoperatively as prophylaxis against cystoid macular edema, which these eyes are at high risk for. These should also be used longer in pseudoexfoliation eyes to prevent other complications such as peripheral anterior synechiae. In addition, he suggested oral carbonic anhydrase inhibitor therapy to prevent postoperative intraocular pressure spikes. If anterior capsule phimosis does occur, he recommended addressing it early. "The Nd:YAG laser can be used to put radial notches in the anterior capsule," he said. "Alternatively, you can enlarge the capsulotomy circumferentially by continued on page 71