Intraocular Lens Power Calculations after Myopic Laser Refractive Surgery: A Comparison of Methods in 173 Eyes

PurposeTo evaluate and compare published methods of intraocular lens (IOL) power calculation after myopic laser refractive surgery in a large, multi-surgeon study.DesignRetrospective case series.ParticipantsA total of 173 eyes of 117 patients who had uneventful LASIK (89) or photorefractive keratectomy (84) for myopia and subsequent cataract surgery.MethodsData were collected from primary sources in patient charts. The Clinical History Method (vertex corrected to the corneal plane), the Aramberri Double-K, the Latkany Flat-K, the Feiz and Mannis, the R-Factor, the Corneal Bypass, the Masket (2006), the Haigis-L, and the Shammas.cd postrefractive adjustment methods were evaluated in conjunction with third- and fourth-generation optical vergence formulas, as appropriate. Intraocular lens power required for emmetropia was back-calculated using stable post-cataract surgery manifest refraction and implanted IOL power, and then formula accuracy was compared.Main Outcome MeasuresPrediction error arithmetic mean ± standard deviation (SD), range (minimum and maximum), and percent within 0 to −1.0 diopters (D), ±0.5 D, ±1.0 D, and ±2.0 D relative to target refraction.ResultsThe top 5 corneal power adjustment techniques and formula combinations in terms of mean prediction errors, standard deviations, and minimizing hyperopic “refractive surprises” were the Masket with the Hoffer Q formula, the Shammas.cd with the Shammas-PL formula, the Haigis-L, the Clinical History Method with the Hoffer Q, and the Latkany Flat-K with the SRK/T with mean arithmetic prediction errors and standard deviations of −0.18±0.87 D, −0.10±1.02 D, −0.26±1.13 D, −0.27±1.04 D, and −0.37±0.91 D, respectively.ConclusionsBy using these methods, 70% to 85% of eyes could achieve visual outcomes within 1.0 D of target refraction. The Shammas and the Haigis-L methods have the advantage of not requiring potentially inaccurate historical information.Financial Disclosure(s)The author(s) have no proprietary or commercial interest in any materials discussed in this article.