title: Error induced by the estimation of the corneal power and the effective lens position with a rotationally asymmetric refractive multifocal intraocular lens.
abstract: OBJECTIVE
  To evaluate the prediction error in intraocular lens (IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position (ELP).
  
  
  METHODS
  Retrospective study including a total of 25 eyes of 13 patients (age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL (Oculentis GmbH, Germany). In all cases, an adjusted IOL power (PIOLadj) was calculated based on Gaussian optics using a variable keratometric index value (nkadj) for the estimation of the corneal power (Pkadj) and on a new value for ELP (ELPadj) obtained by multiple regression analysis. This PIOLadj was compared with the IOL power implanted (PIOLReal) and the value proposed by three conventional formulas (Haigis, Hoffer Q and Holladay I).
  
  
  RESULTS
  PIOLReal was not significantly different than PIOLadj and Holladay IOL power (P>0.05). In the Bland and Altman analysis, PIOLadj showed lower mean difference (-0.07 D) and limits of agreement (of 1.47 and -1.61 D) when compared to PIOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELPadj was significantly lower than ELP calculated with other conventional formulas (P<0.01) and was found to be dependent on axial length, anterior chamber depth and Pkadj.
  
  
  CONCLUSIONS
  Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing the keratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.
authors.affiliation: Grupo de Óptica y Percepción Visual (GOPV). Department of Optics, Pharmacology and Anatomy, University of Alicante, San Vicente del Raspeig, Alicante 03690, Spain ; Department of Ophthalmology (Oftalmar), Vithas Medimar International Hospital, Alicante 03016, Spain ; Foundation for the Visual Quality (FUNCAVIS: Fundación para la Calidad Visual), Alicante 03016, Spain.
authors.forename: David P
authors.initials: DP
authors.lastname: Piñero
authors.affiliation: Grupo de Óptica y Percepción Visual (GOPV). Department of Optics, Pharmacology and Anatomy, University of Alicante, San Vicente del Raspeig, Alicante 03690, Spain.
authors.forename: Vicente J
authors.initials: VJ
authors.lastname: Camps
authors.affiliation: Department of Ophthalmology (Oftalmar), Vithas Medimar International Hospital, Alicante 03016, Spain.
authors.forename: María L
authors.initials: ML
authors.lastname: Ramón
authors.affiliation: Grupo de Óptica y Percepción Visual (GOPV). Department of Optics, Pharmacology and Anatomy, University of Alicante, San Vicente del Raspeig, Alicante 03690, Spain.
authors.forename: Verónica
authors.initials: V
authors.lastname: Mateo
authors.affiliation: Department of Ophthalmology (Oftalmar), Vithas Medimar International Hospital, Alicante 03016, Spain ; Foundation for the Visual Quality (FUNCAVIS: Fundación para la Calidad Visual), Alicante 03016, Spain.
authors.forename: Rafael J
authors.initials: RJ
authors.lastname: Pérez-Cambrodí
keywords: Mplus; effective lens position; intraocular lens power; keratometry; multifocal intraocular lens