Eyeworld

EW CATARACT 44 October 2018 by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer situations with profound zonular di- alysis exceeding 3 clock hours," Dr. Malyugin said. "They can be useful not only in restoring the contour of the capsular bag but also in replac- ing the missing zonules." The Malyugin CTR is a modi- fication of the Cionni CTR, which was designed to eliminate the risk of perforating the capsular bag and is specially adapted for severe zonular dehiscence and dialysis when iris retractors and conventional CTRs cannot fully stabilize the bag. The modified CTR uses an injector, and the device's curved element easi- ly slides along the equator of the capsular bag without damaging the capsule or expanding the zonular defect. It is fixated using scleral sutures. In the case of a patient with hereditary zonular deficiency, Dr. Malyugin proceeded with extreme caution from the start, as the capsulorhexis can be one of the challenging steps in these kinds of eyes. "I used a special hook here, an iris capsule retractor," he said. "I allowed the edge of the hook to rest on the equator, not causing much stress on the edge of the capsule. This helped me perform the contin- uous capsulorhexis. I aspirated part of the cortical material and injected the modified capsular tension ring, making sure that I always inject the device toward the area of the zonular defect. As soon as it was in the bag, I needed to rotate the ally by using a toothless forceps, fish tail technique, strand assisted technique, or they can be implant- ed with the use of an injector. CTR size selection is calculated using the white-to-white plus 1.0 mm. Avail- able sizes are 10 mm, 11 mm, and 12 mm to accommodate different types of eyes, such as myopic eyes, that require a slightly larger CTR. Even when using the right technique and a correctly sized CTR, positioning issues can occur. Placing the CTR into the anterior chamber angle can happen and is hard to retrieve if the arcus senilis is wide or due to difficulties in grasping the tip of the device, particularly for inexperienced surgeons. Similarly, it can be hard to reposition a CTR placed in the ciliary sulcus. Other difficulties include mixed fixation in the bag/sulcus and capsular rupture during implantation, which although rare, is still possible. Eyes with small pupils, often associated with zonular weakness, present a challenge to implantation, making it difficult to place the CTR correct- ly. Also, a CTR may not be enough of a support in a situation in which a widespread zonular defect reveals itself at the very end of surgery, ne- cessitating the placement of scleral wall sutures in order to stabilize the capsule. Modifications "CTR modifications help us stabilize the capsular bag in complicated the anterior capsulorhexis opening is starting to be oval," Dr. Malyugin said. "It means there is not enough support from the zonules, and in these cases, even if I already com- pleted the surgery successfully, I opt for using a CTR at the end of the procedure to redistribute the tension on the zonules along the capsular bag equator." Patients with pseudoexfolia- tion syndrome present their own set of challenges. Despite careful use of phacoemulsification to break down the nucleus in these cases, the procedure can still damage delicate ocular tissues at times. Dr. Malyugin described a cataract surgery he per- formed in which even meticulous care resulted in capsular damage. "When performing phaco in an eye with pseudoexfoliation syndrome, I prefer vertical chop, augmented sometimes with horizontal chop. In that particular case, when I started to aspirate the cortical material, I was actually inadvertently aspirating the capsule and causing an iatro- genic zonular defect that happened because of my 'blind' maneuvers under the iris. I needed to restore the contour of the capsular bag, which I accomplished by injecting viscoelastic into the bag, reposition- ing its fornix, and using a conven- tional CTR to restore bag shape and integrity." Potential issues CTRs are either implanted manu- Specialist describes his implementation of capsular tension rings in dealing with zonular defects I OL implantation in eyes with zonular weakness and crys- talline lens subluxation are challenging cases for cataract surgeons. Identifying the extent of the zonular defect will allow the surgeon to plan the right strategy to achieve a stable IOL implantation. According to Boris Malyugin, MD, S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Russia, capsular tension rings (CTRs) are key elements in cataract surgery to restore the contours and stability of the capsular bag to allow safe and reliable IOL implantation, even in highly complicated cases. "We all love CTRs because they help us in difficult cases involving the zonules," Dr. Malyugin said in his presentation at the 22nd ESCRS Winter Meeting. "However, do not use a CTR if capsular bag integrity is in doubt, like when you have a radi- al tear or posterior capsular rupture, because you might be expanding the defect in the capsule." CTR scenarios The main reason for crystalline lens subluxation is weak zonular fibers. Zonular deficiency has been asso- ciated with a number of etiologies, including hereditary causes such as Marfan syndrome, Weill-Marchesani syndrome, homocystinuria, and congenital iris coloboma, as well as acquired causes like trauma, iatro- genic surgical factors, previous eye surgery, ocular comorbidity (pseu- doexfoliation syndrome, retinitis pigmentosa, myopia, glaucoma), and certain types of cataract (white, intumescent), among others. Ac- cording to Dr. Malyugin, CTRs are helpful in even the most complicat- ed scenarios. Indications for conventional CTR use include generalized zonu- lar weakness (irido-phacodonesis, star-fold formation on the anterior capsule during CCC), local zonular defects not exceeding 90 degrees (3 clock hours), and anterior capsulor- hexis ovalization occurring after IOL implantation. "Sometimes I will use a CTR after I implant a three-piece or single-piece IOL and I see that Compensating for zonular weakness in cataract surgery Presentation spotlight Large zonular defects Source: Boris Malyugin, MD

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