Eyeworld

EW FEATURE 56 by Jena Passut EyeWorld Staff Writer All about support: Capsular tension devices urged for PXF patients with weak zonules ing room," Dr. Condon said. "Cataract surgery in pseudoexfolia- tion patients is the proverbial box of chocolates. You don't know what you're going to be dealing with until you actually get in there and start." Dr. Condon said he knows a case is going to be challenging when he attempts the capsulorhexis and the capsular bag either wrinkles or moves entirely. "It tells you there's not a lot of zonular support going on there," he said. "At that point, I'm already thinking about additional support devices to do the surgery safely." John C. Hart Jr., M.D., co- director of anterior segment surgery, William Beaumont Medical Center, West Bloomfield, Mich., said he rou- tinely uses capsular tension rings in patients with PXF, except in those patients with mild or unilateral dis- ease. Two types of CTRs have been approved for use in the U.S.: the Reform Ring (Morcher GmbH, Stuttgart, Germany) and the StabilEyes Ring (Abbott Medical Optics, AMO, Santa Ana, Calif.). "My plan could change depend- ing on what I find during surgery," Dr. Hart said about using CTRs in surgery. "If I see any phacodonesis or any sign that that might be going on, I'm very quick to pull the trigger to put one in." Dr. Condon said that a CTR doesn't provide enough zonular sup- port to justify its use prior to or dur- ing removal of the crystalline lens. "The stress of inserting it can re- sult in further loss (of zonules) and potentially make the situation worse," he said. Timing, apparently, is crucial. "We found that if you place the ring early, it does cause more stress on the zonules and has more poten- tial for complications," said Iqbal (Ike) K. Ahmed, M.D., assistant pro- fessor, University of Toronto, and clinical assistant professor, Univer- sity of Utah, Salt Lake City. "If you put it in after the bag has been evac- uated, it's much easier to put in and you don't risk having cortex trapped behind it." Alternatives/additions to CTRs Dr. Condon said iris retractors en- large small pupils and hook around the edges of the capsulorhexis to provide support to the capsular bag while a surgeon works on the nu- cleus of the cataract. However, "capsule retractors do the best job of supporting the cap- sule during the surgery," he said. "The nice thing about these is that they go all the way out to the cap- sule equator and not only support the capsular bag but also tension the posterior capsule because the other challenging part of doing surgery on PXF patients is that they often have a very redundant and floppy capsu- lar bag." In order to avoid creating loss of zonular integrity or support during the cataract procedure, capsular ten- sion segments may also be used— either temporarily attached to the limbus after an anterior capsulo- tomy like a retraction device or su- tured to the sclera for long-term stabilization. Dr. Ahmed developed the Ahmed CTS (Morcher), which re- ceived Food and Drug Administra- tion approval in 2010. "It's different from the other re- tractors in that it supports a wide area of the capsular equator, which is the most important part of the bag to support," Dr. Ahmed said. Dr. Condon said that a disper- sive viscoelastic can also be placed to act as a "virtual ring" in the same manner as hydrodissection. "If you inject it just under the capsulorhexis edge so that it goes out under the peripheral part of the capsular bag, it expands it like a CTR but doesn't put any undue stress on the zonules while you're injecting it," he said. "This separates the lens material from the capsular bag and tensions the posterior capsule bag; it stabilizes the entire environment in an easily perceived way and allows for safer, more controlled removal of the residual nuclear material." Advancements in technology and fluidics also allow for a very pre- cise phacoemulsification procedure with minimal stress on the zonules from moving the lens or capsular bag. Dr. Condon suggested adjusting the phacoemulsification machine parameters so that the procedure is putting the least amount of stress on the zonules. "That's very achievable, whether you use chopping techniques or di- vide-and-conquer techniques," he said. "Some of the newer forms of phacoemulsification, particularly the torsional form, allow us to do very gentle phaco on the lens without putting stress on it." Multifocal and torics: To implant or not to implant? There is some controversy about in- serting multifocal or toric IOLs in PXF patients for fear that the unsta- ble capsular bag may lead to mis- alignment of the lens. "Patients have to be aware that while these lenses can be viable in many cases of PXF, there's always the concern that eventual subluxa- tion, or malposition of the capsular bag and lens complex, can lead to ineffectiveness of what they had be- fore, possibly making their vision February 2011 Challenging cataract cases September 2011 Zonular weakness varies in these patients and may present at slit lamp or on operating table P seudoexfoliation syn- drome patients with zonu- lar weakness present a variety of challenges for surgeons during cataract surgery. Physicians, however, have a plethora of choices in their arma- mentarium to help them manage pseudoexfoliation (PXF) zonulopa- thy, including the intraoperative use of capsular tension devices. Surgeons may opt for capsular tension devices to help ease the safe removal of a patient's crystalline lens, as well as place an IOL that will remain central and stable for the long term. The first sign that a surgeon may need to use a capsular tension device due to loss of zonular in- tegrity may present itself during a pre-op slit lamp examination. There, a surgeon might see a mobile or displaced lens or a deepening on one side of the chamber and not the other, according to Garry P. Condon, M.D., chairman, ophthal- mology department, Allegheny General Hospital, Pittsburgh. "You can get some hints pre-op- eratively, but even if things look good in the exam room, they can be completely different in the operat- AT A GLANCE • First indication of a tricky case may be when capsular bag wrinkles or moves during capsulorhexis • Early placement of a CTR may cause unneeded stress on zonules • Alternatives/additions to CTR include iris and capsule retractors, capsule tension segment, and dispersive viscoelastic used as a "virtual ring" • Concerns about misalignment of lens considered before implantation of multifocal or toric lenses in PXF patients with weak zonules • Use of non-steroidals may help combat CME in patients, while prostaglandin use may be continued An eye with two CTRs Source: Iqbal (Ike) K. Ahmed, M.D

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