Eyeworld

67 EW RESIDENTS July 2017 shift with the first two being calcu- lated by Purkinje meter, arguably a more accurate method compared to Scheimpflug imaging. Third, the au- thors performed subgroup analysis based on different IOL materials and design, an important distinction giv- en that three-piece IOLs have been observed to have larger decentration than one-piece IOLs. 8 The limitations of this paper include the following: First, the design of this study was a non-ran- domized single center study; the determinants for why certain rhexes were made less symmetrically or of non-ideal size were not described, thus preventing the analysis of fac- tors contributing to rhexis creation that may possibly affect final IOL position. Second, the paper did not separate eccentric asymmetric rhexes by size, but it would be important to examine IOL decentration in large, eccentric rhexes separately to see if this class of rhexes would be a high- risk category based on the authors' findings that small rhexes result in the least decentration and eccentric rhexes the most. If this holds true, it would be helpful for cataract sur- geons to know the most at-risk types of rhexes for causing poor IOL po- sitioning. Third, the types of lenses most prone to affecting visual out- comes from poor IOL positioning— toric and multifocal IOLs—were not included in this study. Inclusion of these lens types would be a natural next step. Ultimately, to answer the cen- tral question raised by the authors— whether FLACS capsulotomies result in better IOL positioning and thus better visual outcomes compared to manual capsulorhexes—requires further research. Specifically, a randomized, prospective, direct comparison of IOL positioning in cataract surgery with FLACS capsulo- tomy versus manual capsulorhexis is needed to more definitively answer this clinical question. Moreover, refractive outcomes should be included in future studies as this is ultimately what affects patients' quality of life. EW previously validated, the authors provided a well-reasoned explana- tion in the methods. For lens tilt and anterior chamber depth shift, the authors found no statistically significant difference among the three rhexis groups. In terms of lens decentra- tion, the small rhexis group was found to have significantly less decentration compared to the other groups. However, as the authors point out, a smaller rhexis has other drawbacks, such as increased stray light. The authors had a number of interesting secondary endpoints as well. Incomplete rhexis-IOL overlap correlated with anterior chamber depth shift. Change in rhexis size over the 3-month study period was not significantly different among study groups. Finally, the authors looked at IOL type and its effect on the study parameters. Hydrophobic three-piece acrylic lenses were asso- ciated with increased decentration, and hydrophobic one-piece acrylic lenses were associated with rhexis size change over 3 months. The authors' results show that except for severely misformed rhex- es, rhexis size and shape had little effect on IOL tilt, decentration, or anterior chamber depth shift. They concluded that due to the lack of significant differences across these parameters, rhexes of varying pre- cision has little impact on the final refractive outcome. Based on the authors' introduction, they suggest that one of the theoretical advan- tages of FLACS—more precise and rounder capsulotomies—may not result in improved visual outcomes compared to manual capsulorhexes, thus adding to the literature that FLACS may have less benefit than initially expected. This paper has several strengths. First, while most previous studies in- cluded 20 to 60 eyes, Findl et al. in- cluded a large sample size with data for 255 eyes with each group having at least 63 eyes. Second, for each surgery, the authors documented three important metrics of IOL posi- tioning for all cases included in their study: tilt, decentration, and ACD Effect of manual capsulorhexis size and position on intraocular lens tilt, centration and axial position Oliver Findl, MD, Nino Hirnschall, MD, PhD, Petra Draschl, MD, Jörg Wiesinger, MD J Cataract Refract Surg. 2017;43(7). Article in press Purpose: Aim of the study was to evaluate the influence of a manual capsulorhexis size, shape and position on postoperative axial position, tilt, and centration of IOL. Setting: Hanusch Hospital, Vienna, Austria Design: Prospective consecutive monocenter study Methods: Patients scheduled for cataract surgery were included in this prospective study. Follow-ups were performed 1 hour and 3 months after surgery. Postoperatively patients were divided into three groups according to rhexis shape and size (symmetric rhexis between 4.5 mm and 5.5 mm in the control group, below 4.5 mm in the small rhexis group and all others in the eccentric rhexis group). At both follow-ups a retroillumination image, partial coherence interferometry measurements and Purkinje meter measurements were performed. Results: In total, 255 eyes were included in this study. Postoperative absolute ACD shifts in the control, eccentric rhexis and small rhexis groups were 0.31 mm (SD: 0.27), 0.36 mm (SD: 0.24) and 0.26 mm (SD: 0.24) (pANOVA=0.419), respectively. Tilt in the control, eccentric rhexis and small rhexis groups was 4.08 degrees (SD: 2.13), 3.66 degrees (SD: 2.04) and 2.82 degrees (SD: 1.67) (pANOVA=0.370), respectively. Decentration in the control, eccentric rhexis and small rhexis groups was 0.38 mm (SD: 0.23), 0.40 mm (SD: 0.21), and 0.17 mm (SD: 0.08) (pANOVA=0.027), respectively. Conclusions: Rhexis size and shape has little effect on the capsule bag performance of modern IOLs. Only severely misformed rhexes cases showed slightly decentered IOLs. References 1. Mastropasqua L, et al. Scanning electron microscopy evaluation of capsulorhexis in femtosecond laser-assisted cataract surgery. J Cataract Refract Surg. 2013;39:1581–1586. 2. Nagy Z, et al. Initial clinical evaluation of an intraocular femtosecond laser in cataract surgery. J Refract Surg. 2009;25:1053–1060. 3. Nagy ZZ, et al. Femtosecond laser cataract surgery. Eye Vis (Lond). 2015;2:11. 4. Mastropasqua L, et al. Optical coherence tomography and 3-dimensional confocal structured imaging system-guided femtosec- ond laser capsulotomy versus manual con- tinuous curvilinear capsulorhexis. J Cataract Refract Surg. 2014;40:2035–2043. 5. Kranitz K, et al. Intraocular lens tilt and decentration measured by Scheimpflug camera following manual or femtosecond laser-created continuous circular capsuloto- my. J Refract Surg. 2012;28:259–263. 6. Mihaltz K, et al. Internal aberrations and optical quality after femtosecond laser anterior capsulotomy in cataract surgery. J Refract Surg. 2011;27:711–716. 7. Day AC, et al. Laser-assisted cataract sur- gery versus standard ultrasound phacoemulsi- fication cataract surgery. Cochrane Database Syst Rev. 2016;7:CD010735. 8. Crnej A, et al. Impact of intraocular lens haptic design and orientation on decen- tration and tilt. J Cataract Refract Surg. 2011;37:1768–74. Contact information Winn: bjw15@cumc.columbia.edu

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