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Jane Song, Thomas Lawrence Lamson, Azin Abazari, Timothy Chou, Robert A Honkanen, Patricia Pahk, Khurram Chaudhary, Sarah Brown Weissbart; Refractive outcomes of phacoemulsification after pars plana vitrectomy using traditional and new IOL calculation formulas. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2214. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Cataract surgery in vitrectomized eyes presents multiple challenges to cataract surgeons, including IOL calculations and the prediction of residual refractive error. The aim of our study was to evaluate refractive outcomes of phacoemulsification surgery (CE) in patients who have previously undergone pars plana vitrectomy (PPV) and to compare the accuracy of various IOL calculation formulas in this population.
We conducted a retrospective study evaluating refractive outcomes in patients who underwent CE following PPV. We compared the actual refractive outcomes to the predicted refractive errors using the Holladay 1, Wang-Koch-adjusted Holladay 1 (WKA-H1), Holladay 2, SRK/T, Wang-Koch-adjusted-SRK/T (WKA-SRK/T), Barrett, Hill-RBF, and Ladas formulas using Student t-tests and Pearson correlation. The percentages of eyes with prediction errors ≤0.5 D and ≤1.00 D were quantified for each formula. Eyes with silicone oil and a history of corneal refractive surgery were excluded.
The mean±SD postoperative spherical equivalent (SE) was -0.15D±0.81 at postoperative month 1 (n=61). The mean prediction errors were 0.37±0.99, 0.22±1.39, 0.23±0.69, 0.32±0.99, 0.36±1.51, 0.36±1.01, 0.35±0.77, and 0.56±1.20D with the Holladay 1, WKA-H1 (n=15), Holladay 2 (n=58), SRK/T, WKA-SRK/T (n=15), Barrett, Hill-RBF, and Ladas formulas, respectively. Statistically significant differences (p<0.05) between predicted and actual refractive outcomes were found with all formulas except the Holladay 2, WKA-H1, and WKA-SRK/T. A statistically significant correlation was found between the predicted and actual outcomes using the Hill-RBF (R=0.38, p=0.02) and Holladay 2 (R=0.44, p=0.02) formulas. The Holladay 2 formula provided the highest proportion of refractive targets within ±0.50 D (62.5%) and ±1.00 D (87.5%) of the actual postoperative spherical equivalents compared to the other formulas.
Refractive outcomes following CE in vitrectomized eyes may be variable and more hyperopic than the predicted postoperative SE using both traditional and newer IOL calculation methods. Our study suggests that the Holladay 2 formula may provide the closest estimation of postoperative refraction in this population. Future prospective study is warranted to determine the best method of choosing IOL power in vitrectomized eyes.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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