Eyeworld

133 EW SECONDARY FEATURE April 2016 but as for anterior capsule integrity, Dr. Donaldson said, "studies have shown that the tensile strength of a FLACS capsulotomy is actually stronger than a manual capsuloto- my." Taking on astigmatism For patients receiving a multifocal IOL to gain freedom from glasses after cataract surgery, the physician must also correct any astigmatism. Using the proper nomogram can assist the surgeon in plotting the length and depth for LRIs or astig- matic keratomy performed with the laser. Dr. Donaldson said she uses the Nichamin manual LRI nomogram and subtracts 30%. She follows up with the patient 1 month postop and, after a topography, opens the incisions at that time as needed. Dr. McCabe said she used to use the Nichamin LRI nomogram with a diameter of 9 mm at an 80% depth. More recently, however, she has been using the nomogram at www. laserarcs.com, a website developed by Bart Jones, MD, and Michael Jones, MD, with Illinois Eye Sur- geons. Overall, Dr. Weinstock said the vast majority of patients have low amounts of astigmatism or a level that can be corrected with the laser easily. "The laser, with its capacity to do limbal relaxing/arcuate incisions, is one of the tools I use to achieve [customized refractive surgery] for all of my patients," he said. "Wheth- er they can afford to do it or want to get out of glasses, that's up to them." EW Editors' note: Dr. Donaldson has financial interests with Alcon and Abbott Medical Optics. Dr. McCabe has financial interests with Alcon and Bausch + Lomb. Dr. Weinstock has financial interests with Alcon, Bausch + Lomb, and LENSAR. Contact information Donaldson: KDonaldson@med.miami.edu McCabe: cmccabe13@hotmail.com Weinstock: rjweinstock@yahoo.com true cortex for a complete hydrodis- section. "In femto cases, when the laser energy cuts the capsulotomy, it's also cutting that very superficial lay- er of cortex right under the capsule … some people feel the laser energy fuses those together with a little bit of a whitish ring, so it's very hard to get into that space with the hydro- dissection cannula," he said. Dr. Weinstock said he finds the corneal incisions difficult to find and open, so he avoids using femto for them, opting for a manual dia- mond incision. Dr. McCabe, on the other hand, finds the laser effective at creating corneal incisions. She created a cannula specifically to open them—the McCabe 25 Gauge Femto Visco Paddle Cannula E4910 (Bausch + Lomb). Dr. Donaldson said she thinks software upgrades have significantly improved using the laser for this modality. "In earlier FLACS cases, inci- sions were occasionally inadver- tently placed too anterior, inducing irregular astigmatism, corneal edema, and the inability to create a watertight wound without sutures," Dr. Donaldson said. "This problem has lessened with time. If a surgeon continues to struggle with this issue, the wound architecture should be reevaluated and the inner lip of the primary wound may be enlarged to avoid torquing of the wound during phacoemulsification, thus promot- ing better wound closure." Dr. McCabe offered 2 additional pearls for better FLACS outcomes: Clear the corneal surface of debris and size the capsulorhexis slightly larger than the nuclear fragmen- tation pattern. Doing the former, she said, will ensure there are no opacities that could obstruct the effectiveness of the laser, leading to an incomplete capsulotomy. Sizing the capulorhexis about 1 mm larger than the nuclear fragmentation size could help ensure that any gas bub- ble accumulation does not obscure the capsulorhexis edge, allowing the physician to assess and grab a fully free-floating capsule. Verifying the capsulorhexis is complete and without tags is im- portant to avoid a capsule rupture, "It is more difficult for a mon- ocular patient to fixate and remain still for the laser, as they can't use the fellow eye to help maintain fixation," Dr. Donaldson said. "Mon- ocular patients are usually more anxious, which may impact their ability to fully cooperate during the laser procedure, particularly since we don't typically provide any IV sedation until after the laser portion is complete." Dr. McCabe, however, said that in the case of a monocular patient, she would use the laser "as long as there wasn't anything that I thought the femtosecond laser couldn't do as well as manual." Issues to avoid Even with appropriate patient selec- tion, surgeons can encounter some issues with FLACS that could lead to serious complications, the most notable being capsule blowout and a sticky cortex. Dr. Weinstock said that while he has never experienced a cap- sule blowout due to the buildup of volume and pressure in the capsule during FLACS, he understands how it could theoretically occur. To avoid this, he depresses the wound with the cannula to release some of the viscoelastic in the anterior chamber prior to hydrodissection. He also said he is more gentle and slow during hydrodissection. Dr. McCabe recommended surgeons be aware of the posterior extent of the laser treatment and confirm there is no material, such as cortex, plugging the main incision to prevent excess pressure. As for a sticky cortex, Dr. Donaldson and Dr. McCabe said they haven't encountered this, al- though it is not uncommon during the learning curve as a surgeon is transitioning from traditional to femto cataract surgery. Dr. McCabe said she uses a tangential movement to peel the cortex away successfully. Dr. Donaldson recommended mak- ing sure hydrodissection is thorough to loosen any remaining cortex. Dr. Weinstock said cortex re- moval in FLACS can be challenging because it is difficult to get the can- nula between the capsule and the that pressure opens up the round capsulotomy even more." Dr. Weinstock, Dr. McCabe, and Dr. Donaldson said they think fem- tosecond laser lens fragmentation is advantageous compared to tradition- al, manual surgery in patients with dense cataracts. "In a dense cataract, not only will [the femtosecond laser] make a nice capsulorhexis, but it can soften the cataract so that less phaco energy is needed to break up the cataract and remove it," Dr. McCabe said. "It's easier on the eye because it allows less phaco energy to be used, reducing stress on intraocular struc- tures and corneal endothelial cells." As for managing fragmentation time and gas production in these cases, Dr. Weinstock said, for him, it's a "non-issue." "There's going to be gas pro- duction, especially in dense cata- racts—that's the byproduct of the laser energy hitting the tissue—but I've never seen a case that's had so much gas build up that it did any damage to the capsule," he said, adding that it usually gets "burped up under the capsulotomy" and is released through a hole already in the capsule. Dr. McCabe said newer frag- mentation patterns, like the cube pattern, create bubbles that are more dispersed in the lens as well. Dr. Donaldson, who primarily uses the LenSx laser and Catalys laser (Abbott Medical Optics, Abbott Park, Illinois), said she finds femto beneficial in cases of Fuchs' dystro- phy, small eyes, traumatic cataracts, loose zonules, and pseudoexfolia- tion. Drs. Donaldson and Weinstock said patients with a small pupil would not make good FLACS can- didates because it reduces the field through which an adequate laser treatment can be performed. Dr. Weinstock added that he would not use femto on a patient with a glaucoma filtering bleb on the conjunctiva due to the suction rings involved with the laser dock- ing. Dr. Donaldson said she would avoid using the laser on patients who are fidgety or have trouble fix- ating, which could include monocu- lar patients.

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