Eyeworld

24 | EYEWORLD | DECEMBER 2023 ASCRS NEWS References 1. Xu Y, et al. Refractive outcomes and anterior chamber depth after cataract surgery in eyes with and without previous pars plana vitrectomy. Curr Eye Res. 2021;46:1333–1340. 2. Tan X, et al. Accuracy of new generation intraocular lens calculation formulas in vitrec- tomized eyes. Am J Ophthalmol. 2020;217:81–90. Contact Ahmad: samera.ahmad@emory.edu Grosel: tgrosel@emory.edu Jones: jjones2@emory.edu Lin: mung.yan.lin2@emory.edu Raabe: jared.raabe@emory.edu Discussion In their retrospective review, Zhang et al. identified risk factors for refractive prediction error using a large sample size and included two formulas (Hoffer QST and Pearl-DGS) that had not been previously reported in post-vitrectomy eyes. A history of scleral buckling or sulcus IOL placement increased the risk of myopic error, while long axial length (>26 mm) and silicone oil tamponade increased the risk of hyperopic prediction error. Post-vitrectomy eyes overall had significantly lower accuracy with respect to refractive prediction than eyes that had not undergone vitrectomy. The Kane formula had the best overall performance in vitrectomized eyes; however, other formulas performed well in specific situations, such as the Barrett Universal II in eyes that had undergone scleral buckling, which may be due to the inclusion of corneal diameter in the calculation. The authors stated the risk of hyperopic prediction error is too high when traditional formulas are used in post-vit- rectomy eyes with long axial length, so they suggested using the Emmetropia Verifying Opti- cal or Holladay 1 with WKn if the tamponade is with balanced salt solution and using the SRK/T with the first version of the Wang-Koch AL adjustment (WK1) if silicone oil was used. Lim- itations of the study included its retrospective nature, variations in scleral buckling technique, and the intrinsic inaccuracy of manifest refrac- tion measurement in patients with lower visual acuity, which is prevalent in their post-vitrecto- my patient population. continued from page 23 Choice of intraocular lens calculation formula for cataract patients with prior pars plana vitrectomy Zhang J, et al. J Cataract Refract Surg. 2023;49:956–963. n Purpose: To determine the optimal intraocular lens (IOL) calculation formula for vitrectomized eyes with diverse surgical and biometric characteristics n Setting: Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China. n Design: Retrospective consecutive case series study. n Methods: This study included 974 vitrectomized eyes (974 patients) scheduled for phacoemulsification with IOL implantation. Eleven formulas were evaluated: Barrett Universal II (BUII), Emmetropia Verifying Optical, Hoffer QST, Kane, Ladas Super Formula, Pearl-DGS, Radial Basis Function (RBF), Haigis, Hoffer Q, Holladay 1, and SRK/T. Risk factors for prediction error (PE) exceeding 1 diopter (D) were determined using multiple logistic regression. Subgroup analyses were performed based on surgical history and biometric parameters. n Results: The risk of hyperopic PE (>1 D) was higher in patients with silicone oil tamponade (odds ratio [OR], 1.82) and longer axial length (AL) (OR, 1.55), while patients with previous scleral buckling (OR, 2.43) or ciliary sulcus IOL implantation (OR, 6.65) were more susceptible to myopic PE (<–1 D). The Kane formula had the highest overall prediction accuracy and the best in silicone oil-filled eyes and the flat cornea subgroup. The BUII and RBF displayed the optimal performance in eyes with previous scleral buckle and steep cornea, respectively. In eyes with an AL ≥26 mm, the Holladay 1 with the nonlinear version of the Wang-Koch AL adjustment (Holladay 1-WKn) showed the lowest absolute PE and highest percentage within ±1.0 D of PE. n Conclusions: The Kane achieved the highest overall prediction accuracy in vitrectomized eyes. The optimal formula for eyes with previous scleral buckle, steep cornea, or long AL was BUII, RBF, and Holladay 1-WKn, respectively. Several new IOL calculation formulas have improved refractive outcomes in [eyes that have undergone PPV]; however, the optimal IOL calculation formula is still under debate.

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