NEWS & OPINION EWAP SEPTEMBER 2023 57 By Christopher Long, MD, Shaunak Bakshi, MD, Ian Christensen, MD, Abinaya Thenappan, MD, Austin Bohner, MD An EyeWorld Journal Club review Contact information Bakshi: shaunak.bakshi@med.usc.edu Bohner: adbohner@gmail.com Christensen: iantchristensen@gmail.com Long: chrisplong7@gmail.com Song: brian.song@med.usc.edu Thenappan: aat2164@columbia.edu Capsular tension ring against in-the-bag dislocations In - the - bag (ITB) dislocations of an intraocular lens (IOL) after cataract surgery is a rare complication that can detract from the many benefits of cataract surgery. ITB dislocation refers specifically to dislocation of the entire capsule- IOL complex, usually a late (months to years) complication that occurs as a result of zonular weakness induced by anterior capsule contraction. 1,2 Capsular tension rings (CTRs) have been shown to stabilize the capsule intraoperatively in the setting of zonular dehiscence or instability. 3,4 Logically, CTR implantation has been hypothesized as a potential method to reduce the incidence of ITB dislocations. Previous research, however, has been inconclusive. While some studies support the protective effects of CTRs, others suggest CTRs may lead to earlier and more frequent ITB dislocations. 2,5,6,7 Therefore, Mayer-Xanthaki et al. sought to further characterize the impact of CTR implantation on the development of ITB dislocations. Methods This investigation was conducted as a single-center, retrospective cohort study based on medical records at the Medical University of Graz, a tertiary care center in Austria. These data had previously been utilized by some of the authors in a study on the relationship between IOL design and ITB dislocation. 8 The study included patients who received cataract surgery, including extracapsular cataract extraction and phacoemulsification with implantation of a posterior chamber IOL, from July 1996 to July 2017, with identification of postoperative referrals due to IOL dislocations in this time period. ITB dislocation of interest in this study was defined as IOL-capsular bag complex luxation after uncomplicated cataract surgery and IOL implantation. The extracted dataset comprised variables including sex, age, technique of cataract surgery, the operated eye, zonular fiber weakness in surgery, non-sutured CTR insertion during surgery, anterior capsule staining with trypan blue, and noted time to IOL dislocation. Previously reported possible risk factors for IOL dislocation, including pseudoexfoliation (PEX), axial length ≥25.5 mm, uveitis, ocular trauma, and retinitis pigmentosa, were also identified. Cases of intracapsular extraction, intraoperative posterior capsular rupture, combined phacoemulsification and vitrectomy, and IOL dislocations referred from other institutions were excluded. Descriptive statistics included medians and range for the metric variables, and absolute and relative frequencies for the categorical variables. Exploratory univariate and multivariate Cox proportional hazards regression analyses were employed for risk factors and hazard ratios (with determination of 95% confidence intervals), with follow-up time defined as last follow-up noted in the record, date of presentation with IOL dislocation, or estimated life expectancy from the time of surgery (determined based on annual Austrian national census data). The statistical significance threshold was set at a P value of 0.05. Results A total of 68,199 eyes were included in the analysis. Median age at the time of surgery was 76 years. 60.2% of the surgeries were performed in women. Phacoemulsification was performed in 65,143 (95.5%) eyes and extracapsular cataract extraction with manual extraction of the nucleus in 3,056 (4.5%) eyes. One hundred and eleven (0.16%) ITB dislocations were registered. The median number of years between the cataract surgery and the ITB dislocation was 6.8 (range 0.1 to 18.8). For dislocations with and without a CTR, the median number of years was 4.3 (0.4 to 14.9) and 7.0 (0.1 to 18.8), respectively. In the univariable Cox regression analysis and multivariate model, CTR, PEX, weak zonular fibers, uveitis, retinitis pigmentosa young age, and male sex were significantly associated with an ITB dislocation. Large overall IOL This article originally appeared under the headline “EyeWorld Journal Club review” in the July 2023 issue of EyeWorld. It has been slightly modified and appears here with permission from the ASCRS Ophthalmic Services Corp.
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