title: Immersion A-scan compared with partial coherence interferometry: outcomes analysis.
abstract: OBJECTIVE
  To compare 2 methods of axial length measurement, immersion ultrasonography and partial coherence interferometry, and to elucidate surgical outcomes based on immersion measurements.
  
  
  METHODS
  Oregon Eye Institute, Eugene, Oregon, USA.
  
  
  METHODS
  Axial length measurements in 50 cataractous eyes were obtained by optical biometry (IOLMaster, Zeiss Humphrey Systems) and immersion ultrasound (Axis II, Quantel Medical), and the results were compared. Intraocular lens (IOL) power calculations in the same eyes after cataract extraction and posterior chamber IOL implantation were evaluated retrospectively based on the postoperative spherical equivalent prediction error.
  
  
  RESULTS
  Immersion ultrasonography and partial coherence interferometry measurements correlated in a highly positive manner (correlation coefficient = 0.996). Outcomes analysis demonstrated 92.0% of eyes were within +/-0.5 diopter of emmetropia based on immersion axial length measurements.
  
  
  CONCLUSIONS
  Immersion ultrasonography provided highly accurate axial length measurements and permitted highly accurate IOL power calculations.
authors.affiliation: Oregon Eye Institute, Eugene, Oregon, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Packer
authors.forename: I Howard
authors.initials: IH
authors.lastname: Fine
authors.forename: Richard S
authors.initials: RS
authors.lastname: Hoffman
authors.forename: Peggy G
authors.initials: PG
authors.lastname: Coffman
authors.forename: Laurie K
authors.initials: LK
authors.lastname: Brown
mesh_terms: D001699:Biometry / Q000379:methods*; D003941:Diagnostic Techniques, Ophthalmological; D005123:Eye / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D007368:Interferometry / Q000379:methods*; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008027:Light; D017063:Outcome Assessment, Health Care; D018918:Phacoemulsification; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000175:diagnosis* / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014463:Ultrasonography