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Erschienen in:
20.06.2017 | Original Paper
Comparison of formulas and methods for high myopia patients requiring intraocular lens powers less than six diopters
Erschienen in: International Ophthalmology | Ausgabe 4/2018
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Purpose
To determine the best method to minimize postoperative hyperopia and achieve mild myopia in patients requiring low-powered (<6.00 D) MN60MA intraocular lenses (IOLs).
Methods
This retrospective non-comparative case series consists of 32 eyes (20 patients). Postoperative spherical equivalent (SE) refractions were compared using four methods: standard formulas with varying target refractions (Haigis −1.00 D, Hoffer Q −1.75 D, Holladay 1 −1.50 D and SRK/T −1.00 and −1.25 D), axial length adjustment methods for standard formulas targeted for both plano and −0.50 D, Barrett Universal II formula and the Haigis formula using separate constants for plus and minus IOLs (Haigis +/−). SE (mean, standard deviation, median, range), median absolute error (MedAE), prediction errors, percentage SE less than 0.25 D and greater than −1.00 D, percentage SE within ±0.50 and ±1.00 D of the targeted refraction were calculated.
Results
All methods and formulas gave acceptable mean SE refractions ranging from −0.04 to −0.68 D. The Barrett Universal II, Haigis +/−, standard Haigis formula targeted for −1.00 D and the Holladay 1 formula targeted for −1.50 D met stricter criteria of final SE between 0.25 and −1.00 D in 94–100% of eyes and MedAE between 0.37 and 0.51 D. Other methods had more myopic or hyperopic outliers.
Conclusions
For these eyes with high myopia, the Barrett Universal II, Haigis +/−, standard Haigis targeted for −1.00 D and the standard Holladay 1 targeted for −1.50 D formulas produce the best results exceeding established benchmark criteria and minimizing hyperopic surprises.