Eyeworld

JUNE 2022 | EYEWORLD | 55 C Reference 1. Culp C, et al. Clinical and histo- pathological findings in the dead bag syndrome. J Cataract Refract Surg. 2022;48:177–184. easy to miss. He said that exfoliation syndrome seems to pose a "triple threat" to the zonules. Material from exfoliation deposits where the zonules attach to the capsular bag, where the zonules insert to the ciliary body, and on the zonules themselves. "All of this adds up to diffuse weak zonules that can lead to spontaneous dislocation," Dr. Mamalis said. Dr. Mamalis and Dr. Safran also said prior vitreoretinal surgery seems to be associated with late lens-bag dislocations. "There's something about the vitrectomy procedure where the gelatinous vitreous is re- placed by fluid, and that can cause the zonules to stretch and put more stress on them," Dr. Mamalis said, adding that about 20% of late dislocations have had vitrectomy. Dr. Safran said that a lot of fibrosis of the capsular bag seems to be related to late disloca- tion as well. The fibrosis leads to matrix metal- loproteinase production, which can dissolve the zonules over time. On the flip side, some cases of dislocation have a complete lack of fibrosis; the capsules are completely clear and diaphanous. This con- dition has been coined "dead bag syndrome." Dr. Mamalis was a co-author on a paper pub- lished earlier this year in the Journal of Cataract & Refractive Surgery that examined the clinical and histopathological findings of capsular bags and IOLs from dead bag syndrome cases. 1 "These capsules were crystal clear, and when we look at them under pathological analysis, we found there was a splitting of the capsule," Dr. Mamalis said. "There will be an absence of lens epithelial cells, absence of prolif- erative cortical material. In terms of why this is happening, at this point we can only speculate as to the real reason. … It's known that the lens epithelial cells that normally reside even after cataract surgery in the capsular fornix have some factors that act to maintain the capsular bag. … In these cases, the lens epithelial cells are completely absent for reasons we don't understand." Dr. Mamalis emphasized that while the capsular bag-IOL complex dislocates with dead bag syndrome, it is a different entity than late spontaneous lens dislocation. Prevention and treatment From a prevention standpoint, Dr. Safran said it's important to do atraumatic surgery. He also said to clean out the bag well, removing epithe- lial cells that could lead to fibrotic contraction that pulls on zonules. If there is evidence of pseudoexfoliation or weak zonules, he said it's a good idea to place a capsular tension ring, which could give something to lasso onto later should it dislocate. Dr. Safran said he'll place a capsular tension segment and suture to the sclera if things seem loose at the time of surgery. "I'll do that if I think it's likely the patient will have a dislocation in their lifetime," he said, adding, however, that if the patient's expected lifespan isn't long or if they're not that active, he probably would not do this. "You don't want to be doing unnecessary steps that could cause complications, especially if you're not used to doing it. It could be fixed later by someone who is skilled at doing that." Dr. Mamalis shared a few possible preventa- tive strategies as well. He said to make sure the capsulorhexis is an adequate size. This removes some lens epithelial cells, and he mentioned that some people advocate for polishing the capsule. If you start to see the capsulorhexis shrink over time (capsular phimosis), some suggest doing an anterior YAG capsulotomy with four small radial incisions 1–2 mm out- ward from the edge of the rhexis, relieving the phimosis that pulls on the zonules. "[Another] thing physicians talk about is should we be putting a capsular tension ring in the bag to help prevent late postoperative dis- location? I don't know the answer to that. We'd need to put that in a large number of patients, follow them for 10 years, and see what it does," he said. "But I can say be vigilant in following continued on page 56

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