Eyeworld

EW CATARACT 31 July 2018 Kuglen hook (MST) or Lester lens manipulator (MST), to let the CTR land softly as it comes in contact with the capsular bag. Dr. Arbisser said her preference when zonules are severely abnormal is to place 10.0 nylon through the leading eyelet of the CTR, which she then loads into an inserter and uses for- ceps outside the eye to hold the two strings acting as a tether; if you're happy with placement of the CTR, you cut the strings. Dr. Schallhorn said if she is concerned about bag Sometimes it is necessary to place a CTR before the last bit of cortex removal, Dr. Arbisser said, in which case the remaining cor- tex should be viscodissected and dragged to the opening of the CTR without exerting centripetal pres- sure on the zonules. Both Dr. Arbisser and Dr. Ayres said they prefer CTR placement with an inserter, whether it's manually loaded or preloaded. Both also em- phasized the importance of filling the bag with OVD. Dr. Ayres said he will use a suture-assist in some cases or a second instrument, such as a py posterior capsule on stretch. The Chang-modified MST hooks are best as they have a terminal closed loop and don't allow accidental thread- ing by the CTR, she said. Capsular tension rings There's an oft quoted saying from Kenneth Rosenthal, MD, about placing a CTR as early as necessary but as late as possible, and while many still subscribe to this senti- ment, others think it's antiquated information in light of modern devices. Dr. Ayres said that a CTR might be challenging to put in if you hav- en't removed enough of the nucleus and it could make cortical removal difficult, so he'll try to get as much cortex out before placing a CTR. "But if there is so much zonu- lopathy that I think I'm in danger of causing progressive zonulopathy by not supporting the lens, I will put a capsular tension ring in. It depends on the case. If I had to err on the side of earlier or later, I would say earlier is going to be safer," he said. Dr. Schallhorn said if she is at the cortical removal stage with 3 clock hours or less of zonular dialy- sis she'll put a CTR in, preferring the Henderson CTR (FCI Ophthalmics), which she said makes for easier cortical removal. In addition to making cortical removal difficult, Dr. Arbisser has a couple of other sticking points with early CTR placement. Putting it in early has been shown in the Miyake-Apple view to cause zonular stress even when viscodissection is used to make space between the capsule and lens material. "What the CTR did when placed early was reduce the like- lihood during the last throws of phaco for the floppy posterior capsule to come up and get dinged. The capsule expansion hooks from MST … eliminate, in my opinion, any logic to placing a CTR prior to removal of nucleus," Dr. Arbisser said. "Even if you only had hooks that support the anterior capsule, there are other steps you can take to prevent the posterior capsule from flopping upward, and you should protect it with the second hand instrument or dispersive OVD once exposed anyway. The CTR can give a false sense of security for lens cen- tration as well." hydrodissection, "that's a big clue you have an issue." At this point Dr. Arbisser said she'll avoid the usual one-handed rotation using the chopper and the imbedded phaco tip during vertical chop to loosen the nucleus from the corti- cal or epinuclear shell. In the worst cases the nucleus can be chopped in situ without rotation. Sculpting is never a good idea as it can stress subincisional zonules, Dr. Arbisser said. When necessary, for those who prefer divide and conquer, sculpting should be done with an appropriate- ly high ultrasound setting to avoid pushing the nucleus, she said. Dr. Schallhorn tells her residents it's important to keep the nucleus cen- tral and stable as you chop to avoid zonular stress. Capsular tension hooks Dr. Schallhorn said she is ready to place capsule tension hooks, and specifically mentioned Mackool hooks (FCI Ophthalmics, Pem- broke, Massachusetts), after she's seen instability upon creation of the capsulorhexis when there is still nuclear material in the bag. She said the Mackool hooks can be cumber- some to manipulate inside the eye, but they provide "excellent capsular support." She'll make her incisions posterior to the limbus using a Grieshaber stab knife (Alcon, Fort Worth, Texas), although a 25-gauge needle can be used. Dr. Ayres said he's "a strong pro- ponent of as soon as you know, start doing something to stabilize that lens." There are times when he'll start placing hooks before complet- ing the capsulorhexis. "You need to make sure that you're placing the capsule retrac- tors in the meridian or in the clock hours of the zonular dehiscence and if it's a global dehiscence … you'll need three to four hooks evenly spaced throughout the limbus," he said. "You need to make sure the incisions for those hooks don't get in the way of the incisions you need for cataract surgery." Dr. Arbisser mentioned the "hammerhead," or T-shaped Yama- guchi capsular tension hooks, or the Microsurgical Technology (MST, Redmond, Washington) hooks because they evenly distribute the pressure on the capsulorhexis edge and the latter effectively puts a flop- continued on page 33 Placement of a CTR in a patient with a traumatic cataract and zonulysis. In this case, a lens positioning hook is being used to help safely place the CTR in the capsular bag. Subluxation of the crystalline lens in a patient with homocystinuria Watch a video of Dr. Arbisser's technique on EWAR

• Blank Page
• Blank Page (1)