Eyeworld

97 EW FEATURE October 2016 • Challenging and complicated cataract surgery AT A GLANCE • With posterior polar cataracts, there can be a higher risk of complications such as capsule weakness. • Use of ultrasound may be needed to determine IOL power. • Avoiding initial hydrodissection in these cases is advisable because a defect in the posterior capsule may be revealed leading to loss of the nucleus. by Maxine Lipner EyeWorld Senior Contributing Writer as potential weakness in the posteri- or capsule. Signs of a polar cataract There are distinct signs that help distinguish a polar cataract from a posterior subcapsular one. Visually, a posterior polar cataract has a much denser central white plaque than a posterior subcapsular cataract. "It looks like a little white sticker right in the middle of the lens," Dr. Safran said, adding that the rest of the lens may be clear. These are bilateral about 60–85% of the time but may present unilaterally in which case How to spot the signs of posterior polar cataracts and effectively treat them I t's something most practi- tioners are periodically faced with: removing a posterior polar cataract. "You'll see one every couple of months," said Steven Safran, MD, Lawrenceville, New Jersey. "If it doesn't ring a bell, it should because it could cause problems with the surgery." This means being prepared to alter the technique to avoid challenges such Warming up to posterior polar cataracts continued on page 98 the case should be very straight- forward, she added. If not, the case may be a little more challenging because the surgeon won't be able to chop or crack well. After Dr. Dhaliwal gets good hydrodissection and hydrodelin- eation, she makes a central groove and tries to split the lens if possi- ble. Sometimes, it's so soft that the instruments go right through it, she said. If this happens, Dr. Dhaliwal recommended using a second instru- ment to scoop the lens nucleus in toward the center. For viscoelastic, Dr. Dhaliwal prefers dispersive viscoelastic to coat the endothelium, and she specifical- ly uses VISCOAT (Alcon). She added that right before do- ing hydrodissection and hydrodelin- eation, she decompresses the anterior chamber by depressing the wound and allowing viscoelastic to exit. "You want to get a nice cleav- age between the capsule and cortex and allow the balanced salt solution to travel easily around the back of the lens and into a non-pressurized anterior chamber to avoid a posteri- or capsule 'blowout,'" she added. Then, before putting the phaco tip in, replenish the viscoelastic just below the endothelium especially in patients with Fuchs' dystrophy, she suggested. Dr. Hardten also finds that a 5.25 mm rhexis is ideal for all lenses, mainly because it provides a good overlap for the IOL optic. "While it is tempting to use a larger rhexis in patients with a soft lens so that you can more easily perform a supracap- sular technique, it is the ideal lens centration that should define the rhexis size," he said. In soft lenses, Dr. Hardten pre- fers a supracapsular technique. This is almost always possible in these soft lenses, he said. "By using initial hydrodissec- tion and then keeping the cannula in the same location while you con- tinue to slowly inject fluid, you can almost always prolapse the lens into the iris plane and anterior chamber without causing undue pressure on the capsule," he said. "This avoids any tendency for peripheral epinu- clear cataract that otherwise is hard to remove." Dr. Hardten said that either a dispersive or cohesive viscoelastic is likely adequate for these cases, but he prefers to use a moderate weight dispersive to provide endothelial protection. Preferred machine settings Generally, soft lenses do not need much ultrasound energy for nucle- ar disassembly, Dr. Yeu said. The younger the patient, the more likely the lens can be slurped, without ultrasound or the phacoemulsifica- tion tip, only using I/A settings and handpiece. "Softer lenses tend to be sticky and gummy, and will not split very easily," she said. "The two most useful settings for soft lenses are a chop setting that has a higher vacuum and burst/pulse mode and the I/A setting." These lenses can be more safely removed by prolapsing anterior- ly above the lens plane. Dr. Yeu said that trying to disassemble the nucleus can be frustrating, and can often result in bowling out of the lens, which can be quite challenging to remove. "The second instrument tends to be more active with softer lenses, particularly blunt or flat ones like a Koch spatula, and they can actively help scoop pieces out of the capsular bag as well as keep the posterior capsule back," she said. Dr. Dhaliwal said that she uses a venturi-based system. The vacuum- based system works well, she said, because you can build vacuum with- out occlusion, and minimal phaco power is needed. High vacuum can help to efficiently remove the nucle- us, Dr. Dhaliwal said. She noted that technique may need to be modified in these soft lens cases. Physicians can't think they'll do a divide and conquer on these lenses because they'll end up bowling it out, she said. In nearly all of her cases, Dr. Dhaliwal said she uses a stop and chop technique. Dealing with a "bowl" The "bowl" effect occurs when the physician is unable to effectively draw the entire piece of the nucleus out of the capsular bag, Dr. Yeu said. "If I notice that the lens is soft and sticky, leading to a 'bowl' effect of the first few attempts, I will switch to the Koch spatula and perform a reverse chop in order to lift the piec- es out of the capsular bag," she said. "If a bowl has been created, coming out of the eye and performing a viscodissection of the epinuclear shell and removing its adhesions to the capsular bag can be exceedingly helpful." This will make it a safer procedure, and depending on the density of the epinuclear bowl or shell that is left, the removal may be completed with the I/A handpiece, Dr. Yeu added. Additionally, coaxial I/A ports tend to be larger than that on the bimanual port and can be more effective at aspirating the soft lens through, she said. Additional tips Dr. Dhaliwal noted that when a sur- geon is operating on soft cataracts or performing a clear lensectomy in a refractive lens exchange, patient selection prior to surgery is incredi- bly important. Although these cases can be gratifying, Dr. Dhaliwal cautioned that for highly myopic patients, there is clear literature stating that these patients have a higher rate of retinal detachment after cataract surgery or lensectomy. This can be a devastating complication for the patient, so Dr. Dhaliwal warned about the impor- tance of being aware of the risks and educating the patient. EW Editors' note: Dr. Dhaliwal has fi- nancial interests with Bausch + Lomb (Bridgewater, New Jersey). Dr. Yeu has financial interests with Abbott Medical Optics (Abbott Park, Illinois), Alcon, and Bausch + Lomb. Dr. Hardten has no financial interests related to his comments. Contact information Dhaliwal: dhaliwaldk@upmc.edu Hardten: drhardten@mneye.com Yeu: eyeulin@gmail.com Pearls continued from page 95 there may be an increased risk of amblyopia. "The patient may tell you, 'I've always had a cataract—I was born with it,' as these are con- genital, but they often progress over time and can become symptomatic when they were not previously," he said. Patients with posterior polar cataracts may complain of glare while driving at night, but might be able to see around the cataract and have surprisingly good chart vision. "A patient could easily be 20/20

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