title: Can the accuracy of multifocal intraocular lens power calculation be improved to make patients spectacle free?
abstract: OBJECTIVE
  To optimise intraocular lens (IOL) power calculation techniques for a segmental multifocal IOL, LENTIS™ MPlus(®) (Oculentis GmbH, Berlin, Germany) and assess outcomes.
  
  
  METHODS
  A retrospective consecutive non-randomised case series of patients receiving the MPlus(®) IOL following cataract surgery or clear lens extraction was performed at a privately owned ophthalmic hospital, Midland Eye, Solihull, UK. Analysis was undertaken of 116 eyes, with uncomplicated lens replacement surgery using the LENTIS™ MPlus(®) lenses. Pre-operative biometry data were stratified into short (<22.00 mm) and long axial lengths (ALs) (≥22.00 mm). IOL power predictions were calculated with SRK/T, Holladay I, Hoffer Q, Holladay II and Haigis formulae and compared to the final manifest refraction. These were compared with the OKULIX ray tracing method and the stratification technique suggested by the Royal College of Ophthalmologists (RCOphth).
  
  
  RESULTS
  Using SRK/T for long eyes and Hoffer Q for short eyes, 64% achieved postoperative subjective refractions of ≤±0.25 D, 83%≤±0.50 D and 93%≤±0.75 D, with a maximum predictive error of 1.25D. No specific calculation method performed best across all ALs; however for ALs under 22 mm Hoffer Q and Holliday I methods performed best.
  
  
  CONCLUSIONS
  Excellent but equivalent overall refractive results were found between all biometry methods used in this multifocal IOL study. For eyes with ALs under 22 mm Hoffer Q and Holliday I performed best. Current techniques mean that patients are still likely to need top up glasses for certain situations.
authors.affiliation: School of Biomedical Sciences, University of Ulster, Coleraine, NI, UK.
authors.forename: Hasnain
authors.initials: H
authors.lastname: Ramji
authors.affiliation: School of Biomedical Sciences, University of Ulster, Coleraine, NI, UK; Cathedral Eye Clinic, York Street Belfast, NI, UK.
authors.forename: Johnny
authors.initials: J
authors.lastname: Moore
authors.affiliation: School of Biomedical Sciences, University of Ulster, Coleraine, NI, UK.
authors.forename: C B Tara
authors.initials: CB
authors.lastname: Moore
authors.affiliation: School of Biomedical Sciences, University of Ulster, Coleraine, NI, UK; Birmingham and Midland Eye Centre, Birmingham, UK; Midland Eye, Solihull, UK. Electronic address: sunilshah@doctors.net.uk.
authors.forename: Sunil
authors.initials: S
authors.lastname: Shah
mesh_terms: D001699:Biometry / Q000295:instrumentation*; D002387:Cataract Extraction; D005139:Eyeglasses; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular / Q000592:standards*; D049451:Nomograms; D055095:Optics and Photonics / Q000592:standards*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology
keywords: Formula; Intraocular; Multifocal; Optimisation; Ray; Tracing