title: Positional accommodative intraocular lens power error induced by the estimation of the corneal power and the effective lens position.
abstract: OBJECTIVE
  To evaluate the predictability of the refractive correction achieved with a positional accommodating intraocular lenses (IOL) and to develop a potential optimization of it by minimizing the error associated with the keratometric estimation of the corneal power and by developing a predictive formula for the effective lens position (ELP).
  
  
  METHODS
  Clinical data from 25 eyes of 14 patients (age range, 52-77 years) and undergoing cataract surgery with implantation of the accommodating IOL Crystalens HD (Bausch and Lomb) were retrospectively reviewed. In all cases, the calculation of an adjusted IOL power (P(IOLadj)) based on Gaussian optics considering the residual refractive error was done using a variable keratometric index value (n(kadj)) for corneal power estimation with and without using an estimation algorithm for ELP obtained by multiple regression analysis (ELP(adj)). P(IOLadj) was compared to the real IOL power implanted (P(IOLReal), calculated with the SRK-T formula) and also to the values estimated by the Haigis, HofferQ, and Holladay I formulas.
  
  
  RESULTS
  No statistically significant differences were found between P(IOLReal) and P(IOLadj) when ELP(adj) was used (P = 0.10), with a range of agreement between calculations of 1.23 D. In contrast, P(IOLReal) was significantly higher when compared to P(IOLadj) without using ELP(adj) and also compared to the values estimated by the other formulas.
  
  
  CONCLUSIONS
  Predictable refractive outcomes can be obtained with the accommodating IOL Crystalens HD using a variable keratometric index for corneal power estimation and by estimating ELP with an algorithm dependent on anatomical factors and age.
authors.affiliation: Department of Optics, Pharmacology and Anatomy, Group of Optics and Visual Perception, University of Alicante, Alicante; Department of Ophthalmology, Medimar International Hospital, Alicante; Foundation for the Visual Quality (FUNCAVIS), Alicante, Spain.
authors.forename: David P
authors.initials: DP
authors.lastname: Piñero
authors.forename: Vicente J
authors.initials: VJ
authors.lastname: Camps
authors.forename: MarIa L
authors.initials: ML
authors.lastname: Ramón
authors.forename: Verónica
authors.initials: V
authors.lastname: Mateo
authors.forename: Rafael J
authors.initials: RJ
authors.lastname: Pérez-CambrodI
mesh_terms: D000368:Aged; D002387:Cataract Extraction; D003315:Cornea / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D019591:Pseudophakia / Q000503:physiopathology* / Q000628:therapy; D012029:Refraction, Ocular; D012189:Retrospective Studies; D014792:Visual Acuity