Eyeworld

EW CATARACT 24 February 2019 Research highlight by Maxine Lipner EyeWorld Senior Contributing Writer to decide between placing a pupil expansion ring versus hooks in a rock-hard cataract case, if there is any question about the zonules, Dr. Foster is more likely to opt for hooks. Then he not only has these in place for expanding the pupil, but also if the zonules prove to be somewhat lax, it's easy to push these forward and grab the capsule edge. Emerging instrumentation Dr. Foster finds the miLOOP (Carl Zeiss Meditec, Jena, Germany) is also potentially helpful in manag- ing such cases. This instrument has a nitinol ring that when retracted becomes very small so that it can go through an incision, Dr. Foster explained. "But once it's in the eye, you can slowly open the ring and you can feed that loop underneath the capsule until at full extension it can be rotated around so that it's back behind the entire cata- ract," he said. "Then, as you close the loop back to its small size, it physically cuts through the lens." One advantage of it is that it applies great pressure from the posterior to the anterior through the posterior leathery plate, which can be difficult to treat with standard phaco since you can't crack it. Meanwhile, when trying to cut this with a vibrating phaco needle, you're just 0.5 mm away from the posterior capsule, Dr. Foster pointed out. Overall, Dr. Foster hopes that practitioners come away from this study on rock-hard cases aware that these can usually be effectively man- aged to the benefit of the patient and that there are modifications that are required to increase the chances of success. "If carefully implemented, surgeons and patients alike can anticipate good results even though it's a more challenging circumstance," he concluded. EW Reference 1. Foster GJL, et al. Phacoemulsification of the rock-hard dense nuclear cataract: options and recommendations. J Cataract Refract Surg. 2018;44:905–916. Editors' note: Dr. Foster has no finan- cial interests related to his comments. Contact information Foster: gjlfos@gmail.com is delivering phaco energy the maximum distance away from the cornea," Dr. Foster said. With phaco energy in rock- hard cases, you generally have to work with higher phaco settings in terms of stroke length, Dr. Foster noted. "Some surgeons advocate using higher levels of vacuum and aspiration to overcome the repul- sive forces of greater stroke length and to overcome the more dense nuclei," he said, adding that in most of these cases, to protect the cornea, you have to stop at least once, if not more, to replenish the OVD in the eye because of the higher flow and the higher amounts of time spent on the removal process. In cases that require zonu- lar protection, if any weakness is noted early on, use hooks to further stabilize the zonules so that you can minimize disruption, Dr. Foster advised. While sometimes surgeons will use a capsular tension ring in the eye in the face of loose zonules, this is particularly difficult to do in these cases because the lens is so big and noncompliant. "Sometimes there's no room to squeeze that capsular tension ring in between the capsule and the large nucleus, so you have to stabilize it with hooks and put the capsular tension ring in later when there's actually room to place it," Dr. Foster said. It's also not uncommon to have to deal with small pupils in these rock-hard cases. When trying Altering management techniques Slightly different management prin- ciples may apply in these rock-hard cases. "If you're going to hydro-dis- sect, it needs to be a very gentle dissection because the lens is so big that it's easy for the fluid wave to become entrapped, and the subse- quent pressure would blow out the posterior capsule," Dr. Foster said. "One of the general recommenda- tions of the Committee is that you create a trench if you're going to chop the nucleus," he said, adding that this can be located central to the capsulorhexis and moving up one-third of the nucleus toward the center. This creates working room for practitioners to try and pull piec- es in centripetally. For surgeons who prefer a divide and conquer technique, investigators recommended that the troughs be about twice as wide as they would for a standard nucleus to create the needed working distance. "These are hard enough and brittle enough that except in the posterior leathery plate, you can crack these through and that wide distance doesn't work against you," he said. The wider space would be an issue with a softer nucleus, in which you want to keep all of the nuclear bulk that you can so that you have some- thing to push against but is not an issue in rock-hard cases. "Plus, all of that energy to create a trench Learning to roll with a rock-hard nuclear case D ealing with a rock-hard cataract can be very differ- ent than performing stan- dard phacoemulsification. As part of a study that appeared in the Journal of Cataract and Refractive Surgery, 1 members of the ASCRS Challenging and Com- plex Cataract Surgery Subcommittee honed in on how to most safely address challenges in such cases, according to Gary Foster, MD, Fort Collins, Colorado. Treating rock-hard lenses differs from a typical phacoemulsification in a variety of ways. "First, the overall density of the lens requires more phaco energy to dismantle the nucleus, so you need to make provisions to protect the cornea in the face of that greater energy," Dr. Foster said. "Second, the lens is usu- ally much thicker than a traditional lens, so you have more girth to deal with but also the working condi- tions are a little tighter." Third, since the red reflex is often signifi- cantly diminished, accomplishing the capsulorhexis is more difficult, he continued, adding that the cap- sule itself may also be more scarred, making its management difficult. In addition, often there's a particularly leathery posterior plate, which may keep the nucleus from cracking, Dr. Foster noted. Up to the challenge Brunescent dense cataract Source: Rosa Braga-Mele, MD

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