Multifocal IOL implantation after corneal refractive laser surgery for myopia resulted in good visual acuity and refraction. Results were less predictable with myopia greater than 6.0 D.

PURPOSE: To compare the accuracy of different intraocular lens (IOL) calculation formulas available on the American Society of Cataract and Refractive Surgery (ASCRS) post-refractive surgery IOL power calculator for the prediction of multifocal IOL power after previous corneal refractive laser surgery for myopia. METHODS: An analysis and comparison were performed of the accuracy of three methods using surgically induced change in refraction (ie, Masket, Modified Masket, and Barrett True-K formulas) and three methods using no previous data (ie, Shammas, Haigis-L, and Barrett True-K No History formulas). The average of all formulas was also analyzed and compared. RESULTS: Thirty-six eyes of 36 patients were included. All formulas, except for the Masket, Modified Masket, and Barrett True-K formulas, had myopic mean numerical errors that were significantly different from zero ( P ⩽ .01). The median absolute error of the Shammas formula (0.52 diopters [D]) was significantly higher compared to all of the other formulas ( P < .05), except for the Haigis-L formula ( P = .09). Comparing the formulas using no previous data, the Barrett True-K No History formula had the lowest median absolute error (0.33 D, P < .001). CONCLUSIONS: The Shammas formula showed the least accuracy in predicting IOL power in eyes with multifocal IOL implantation after previous corneal refractive laser surgery for myopia. In eyes with all available data, all formulas performed equally except for the Shammas formula, whereas in eyes lacking historical data, the Barrett True-K No History formula performed best. [ J Refract Surg . 2019;35(1):54–59.]

ABSTRACT.Purpose: To evaluate whether the automated refraction (AR) correlates with subjective manifest (MR) refraction in eyes implanted with radially asymmetric multifocal intraocular lens (IOLs). Methods: This retrospective study evaluated 52 eyes (52 patients) implanted with a radially asymmetric multifocal IOL (LS-312 MF30, Oculentis, Germany). At 3 months postoperatively, the AR and MR values were compared to determine the correlation between the sphere (S), the spherical equivalent (SE) and the astigmatic components J0 and J45. Results: The difference of mean spherical measurement was +0.98D AE 0.62, with the AR measuring more myopic. The difference of the mean spherical equivalent was +1.11D AE 0.57, again with AR being more myopic. Both these differences were statistically significant (p < 0.001). The astigmatic components showed less differences, with the mean difference of the J0 being À0.09D AE 0.43, and the J45 of +0.04D AE 0.47, which were both not statistically significant (p = 0.123 and p = 0.531, respectively). Correlation analysis of the refractive parameters showed r 2 = 0.067, r 2 = 0.078, r 2 = 0.018 and r 2 = 0.015, respectively, all of which point to a low correlation between the AR and the MR. Conclusion: Autorefraction shows poor correlation to manifest subjective refraction with these radially asymmetric multifocal IOLs. The autorefraction systematically underestimates the spherical and spherical equivalent power, while the correlation between the astigmatic components was also low. Autorefraction seems not a valid starting point for manifest subjective refraction with these types of lenses, unless a corrective factor of about +1 dioptre is used.