title: Comparing ultrasound biometry with partial coherence interferometry for intraocular lens power calculations: a randomized study.
abstract: OBJECTIVE
  To determine whether intraocular lens (IOL) power calculations for cataract surgery as measured by postoperative refractive error using partial coherence interferometry (PCI) are more accurate in improving postoperative outcomes than applanation ultrasound biometry (AUS).
  
  
  METHODS
  A double-blind randomized controlled trial consisting of 205 patients was undertaken by the Southern Health Ophthalmology Unit, Victoria, Australia. Mean absolute postoperative refractive error (MAE) represented the dependent variable; the biometric technique (PCI; AUS) used to determine the IOL power to be implanted in the surgical eye represented the independent variable. An intention-to-treat analysis was used to prevent loss of randomization caused by the effects of crossover and drop-out.
  
  
  RESULTS
  The MAE in patients with implanted PCI-calculated IOLs was 0.40 +/- 0.37 D (SD; 95% confidence interval [CI], 0.32-0.48 D) compared with 0.45 +/- 0.41 D (SD; 95% CI, 0.36-0.54 D) for patients with implanted AUS-calculated IOLs. There was no statistically significant difference between MAE in patients with implanted PCI-calculated IOLs and that in patients with AUS-calculated IOLs in analysis of best possible outcomes (t(167) = 1.0, P = 0.315).
  
  
  CONCLUSIONS
  The results of this trial demonstrated that the calculation of IOL power based on ocular axial length measurement with PCI technology provided no clinical advantage over conventional applanation ultrasound, as measured by postoperative refractive outcome (anzctr.org.au number, ACTRN12608000077369).
authors.affiliation: Department of Surgery, Monash University, Victoria, Australia.
authors.forename: Simon
authors.initials: S
authors.lastname: Raymond
authors.forename: Ian
authors.initials: I
authors.lastname: Favilla
authors.forename: Linda
authors.initials: L
authors.lastname: Santamaria
mesh_terms: D000368:Aged; D000869:Anterior Eye Segment / Q000473:pathology; D001699:Biometry; D004311:Double-Blind Method; D005123:Eye / Q000473:pathology; D005260:Female; D006801:Humans; D007368:Interferometry / Q000379:methods*; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008027:Light; D008297:Male; D033401:Microscopy, Acoustic / Q000379:methods*; D018918:Phacoemulsification; D011184:Postoperative Period; D011446:Prospective Studies; D019591:Pseudophakia / Q000503:physiopathology*; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000503:physiopathology*