Abstract
Purpose :
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.
Methods :
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.
Results :
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).
Conclusions :
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.