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Andrea N Bordewyk, Catherine Seeger, Brett Ernst, Ingrid U Scott, Seth Pantanelli; Optimizing Cataract Surgery Refractive Outcomes in Long Eyes: A Comparison of 5 Formulas. Invest. Ophthalmol. Vis. Sci. 2020;61(7):1679.
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© ARVO (1962-2015); The Authors (2016-present)
Intraocular lens (IOL) power prediction formulas are known to under-perform in axial myopes, with fewer eyes achieving a satisfactory refractive result. The purpose of this study was to compare the accuracy of 5 IOL power prediction formulas with respect to postoperative residual refractive error in eyes with axial length (AL) greater than 25.0 mm.
Retrospective chart review of eyes with AL greater than 25.0 mm that underwent cataract extraction with implantation of a hydrophilic acrylic monofocal IOL (Akreos AO60 , Bausch & Lomb) between November 2014 and June 2018 by a single surgeon. Eyes were excluded from the study if they had previous ocular surgery or trauma, ocular inflammatory conditions, vision-limiting corneal, retinal, or optic nerve disease, a complication or combined procedure during cataract surgery, lack of follow-up, or a postoperative best-corrected visual acuity worse than 20/40. Residual refractive error for each eye was predicted for the implanted IOL power using 5 formulas [SRK/T, Holladay1 (H1), original Wang-Koch adjusted Holladay1 (o-WKH1), Linear Wang-Koch adjusted Holladay1 (l-WKH1), and Non-linear Wang-Koch adjusted Holladay1 (n-WKH1)]. The refractive prediction error of each formula was then calculated as the difference between the actual postoperative refraction and the predicted refraction.
Among the 213 eyes included in the study, the mean prediction error (MPE) was 0.29, 0.42, 0.00, 0.05, and 0.20 D for the SRK/T, H1, o-WKH1, l-WKH1, and n-WKH1, respectively (p < 0.0001). The proportion of eyes within 0.5 D of predicted spherical equivalent was 66%, 59%, 68%, 65%, and 69%, respectively (p = 0.013). SRK/T, o-WKH1, and n-WKH1 each performed significantly better than H1 in terms of proportion of eyes within 0.5 D (p=0.019, p=0.027, p=0.0025). Hyperopic outcomes occurred in 71%, 80%, 46%, 52%, and 66% of eyes, respectively (p <0.0001). Pair-wise comparisons revealed that no two formulas performed the same in terms of hyperopic outcomes (each p value <0.028).
Each of the three Wang-Koch adjusted Holladay1 equations had lower MPEs and lower proportions of hyperopic outcomes than both the SRK/T and Holladay1 formulas.
This is a 2020 ARVO Annual Meeting abstract.
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