title: Comparison of Accuracy in Intraocular Lens Power Calculation by Measuring Axial Length with Immersion Ultrasound Biometry and Partial Coherence Interferometry.
abstract: OBJECTIVE
  To re-examine relative accuracy of intraocular lens (IOL) power calculation of immersion ultrasound biometry (IUB) and partial coherence interferometry (PCI) based on a new approach that limits its interest on the cases in which the IUB's IOL and PCI's IOL assignments disagree.
  
  
  METHODS
  Prospective observational study of 108 eyes that underwent cataract surgeries at Taksin Hospital. Two halves ofthe randomly chosen sample eyes were implanted with the IUB- and PCI-assigned lens. Postoperative refractive errors were measured in the fifth week. More accurate calculation was based on significantly smaller mean absolute errors (MAEs) and root mean squared errors (RMSEs) away from emmetropia. The distributions of the errors were examined to ensure that the higher accuracy was significant clinically as well.
  
  
  RESULTS
  The (MAEs, RMSEs) were smaller for PCI of (0.5106 diopter (D), 0.6037D) than for IUB of (0.7000D, 0.8062D). The higher accuracy was principally contributedfrom negative errors, i.e., myopia. The MAEs and RMSEs for (IUB, PCI)'s negative errors were (0.7955D, 0.5185D) and (0.8562D, 0.5853D). Their differences were significant. The 72.34% of PCI errors fell within a clinically accepted range of ± 0.50D, whereas 50% of IUB errors did.
  
  
  CONCLUSIONS
  PCI's higher accuracy was significant statistically and clinically, meaning that lens implantation based on PCI's assignments could improve postoperative outcomes over those based on IUB's assignments.
authors.forename: Varee
authors.initials: V
authors.lastname: Ruangsetakit
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001699:Biometry / Q000379:methods*; D002387:Cataract Extraction; D005260:Female; D006801:Humans; D007368:Interferometry / Q000379:methods*; D007910:Lenses, Intraocular / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012030:Refractive Errors / Q000503:physiopathology*; D015203:Reproducibility of Results; D013785:Thailand