EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/87458
68 EW FEATURE February 2011 Challenging cataract cases October 2012 Weakened zonules by Michelle Dalton EyeWorld Contributing Writer Weakened zonular support presents numerous issues for the cataract surgeon R educed zonular support can be caused by trauma, pseudoexfoliation, or congenital coloboma, among others. Miscalcu- late how to approach cataract surgery in these cases and it's possible the remaining zonules can disinsert and surgeons will have to perform a vitrectomy, adding more trauma to an already weakened system. In the case that follows, Richard Tipperman, M.D., head, Cataract and Refractive Surgery Complication Management, Oph- thalmic Partners of Pennsylvania and New Jersey, Bala Cynwyd, Pa., describes a case of weakened zonules AT A GLANCE • Zonular weakness or laxity in traumatic cataract is similar to pseudoexfoliation cases • Use of a femtosecond laser can help prevent further zonular damage • Without a femtosecond laser, consider making a smaller capsulorhexis and/or using a three-piece IOL for additional support after decades-old trauma and how the femtosecond laser for refractive cataract surgery "let me take this very high risk case and complete it successfully with minimal trauma." Said Dr. Tipperman: A 43- year-old woman was referred in for cataract surgery; best corrected vi- sual acuity (BCVA) in the right eye was 20/20 and in the left eye, 20/60. She had had blunt trauma in her left eye (poked by a stick) at age 14. Her spectacle correction was OD –2.00, OS –2.75 +0.75 x 45; IOP was normal in both eyes. On slit lamp exam, we found 3+ central nuclear lens change and zonular disruption. "The patient's primary com- plaints were glare and that her visual function was getting progressively worse," Dr. Tipperman said. "Her local ophthalmologist had recom- mended putting off the surgery for as long as possible, and she believed she was at that point." Losing capsular support during cataract surgery "compromises how you're going to put the implant in the eye and creates the potential for posterior dislocation of the nucleus or lens fragments, which increases the complications of surgery," Dr. Tipperman said, and "any case where zonules are weak or lax" is at increased risk. Removing these types of cataracts earlier rather than later is beneficial, said William B. Trattler, M.D., director, Cornea, Center for Excellence in Eye Care, Miami. "The stiffer the cataract is, the more difficult this procedure will be." How the case progressed "We used a femtosecond laser to create a centered 4.9 mm capsu- lorhexis, soften and divide the lens nucleus, and create the primary, secondary, as well as arcuate corneal incisions," Dr. Tipperman said. "We opened the incisions with a blunt spatula and filled the anterior cham- ber with OVD. We prolapsed the nucleus out of the capsular bag, and the remainder of the lens cortex was removed with a combination of manual and automated irrigation/ aspiration. During the I/A portion of the procedure, it was apparent that in addition to the area of focal trau- matic zonular absence, the remain- ing zonules were quite lax, as was the capsule, implying a significant reduction in zonular support. We placed a single-piece acrylic IOL within the capsular bag oriented away from the zonular dehiscence. Post-op day 1 VA was 20/100. At 3 weeks post-op, uncorrected VA is 20/40 and with a refraction of plano +0.50 x 120, she is 20/30." This was a case "that was ab- solutely expertly handled," said Eric D. Donnenfeld, M.D., partner, Oph- thalmic Consultants of Long Island (OCLI), Rockville Centre, N.Y., and clinical professor of ophthalmology, NYU Medical School, New York. "Managing patients who have zonu- lar issues is one of the most chal- lenging aspects of cataract surgery. The most difficult part of the cataract surgery is performing the capsulorhexis without causing fur- ther zonular weakness with dehis- cence, which can convert a case from difficult to one that may in- volve extensive manipulation and possibly an anterior chamber lens." In his opinion, an overlooked benefit of femtosecond technology is its use in cases of zonular weak- ness. "The femtosecond laser doesn't traumatize the eye, it allows a per- fectly centered capsulorhexis, and it doesn't expose an enclosed system, so the lens can maintain its position rather than vaulting forward when the anterior chamber is open, which is what occurs when an incision is opened," he said. Making a manual capsulorhexis puts traction on the zonules, and can lead to significant zonular damage, Dr. Trattler added. "This patient did so well with the help of the femtosecond laser because the surgeon could preserve so many of the remaining zonules," Dr. Trattler said. Why so complicated In cases of traumatic zonular rup- ture, surgeons are unable to deter- mine how loose the whole bag is until they're inside, Dr. Tipperman said. "While some surgeons may Monthly Pulse Keeping a Pulse on Ophthalmology egarding intraoperative aberrometry, were it available and free to use, we have a 60/40 split between those who would use it anywhere from often to all the time vs. those who'd use it occasionally or never. We all know this ratio has to get smaller as the cost to buy and use the equipment be- comes greater, but we don't really know how linear this rela- tionship is or where things will settle if the cost remains as it is currently. Eleven percent of participants stated that they would "never" use it even if it were free. I wonder if this is because they feel they don't need it or don't trust the data generated enough to have it alter their surgical plan? This poll certainly reveals that cost is a major barrier to the acceptance of this technology (as nowhere near 60% of people currently use it), but is it the only one? Twenty percent of respondents would do a pars plana tap on short eyes with a shallow anterior chamber. This is surpris- ing, and I sense that in the real world, most surgeons would wait until they were actually facing a surgical obstacle created by posterior pressure and chamber shallowing before they'd do a blind pars plana tap. We know that in these very small eyes, R the pars plana may be much smaller and the retina insert more anterior than normally, so this is something that surgeons deal- ing with these eyes will want to consider when they make the decision to go through the pars. Almost 80% of respondents are doing cataract surgery without a block, and only 7% use retrobulbar injections. It makes one wonder what the legal ramifications are if a patient developed a complication related to a retrobulbar block (say an optic neuropathy, intractable diplopia, or globe penetration) for a surgeon who blocks on every case if the patient wasn't given informed consent on other options (like topical/intracameral) that could have avoided that risk altogether. It's clear from this poll that many surgeons are not ready to jump on a bilateral simultaneous surgery bandwagon yet. Sixty percent of respondents would "never do it because it's a bad idea." I wonder what percentage of that 60% would draw a firm line in the sand against balanced salt solution under all circumstances? I'm sure the number would drop signifi- cantly—how much is anyone's guess. Steven Safran, M.D., cataract editorial board member