title: Predictability of intraocular lens calculation and early refractive status: the Infant Aphakia Treatment Study.
abstract: OBJECTIVE
  To report the accuracy of intraocular lens (IOL) power calculations and the early refractive status in pseudophakic eyes of infants in the Infant Aphakia Treatment Study.
  
  
  METHODS
  Eyes randomized to receive primary IOL implantation were targeted for a postoperative refraction of +8.0 diopters (D) for infants 28 to 48 days old at surgery and +6.0 D for those 49 days or older to younger than 7 months at surgery using the Holladay 1 formula. Refraction 1 month after surgery was converted to spherical equivalent, and prediction error (PE; defined as the calculated refraction minus the actual refraction) and absolute PE were calculated. Baseline eye and surgery characteristics and A-scan quality were analyzed to compare their effect on PE.
  
  
  METHODS
  Prediction error.
  
  
  RESULTS
  Fifty-six eyes underwent primary IOL implantation; 7 were excluded for lack of postoperative refraction (n = 5) or incorrect technique in refraction (n = 1) or biometry (n = 1). Overall mean (SD) absolute PE was 1.8 (1.3) D and mean (SD) PE was +1.0 (2.0) D. Absolute PE was less than 1 D in 41% of eyes but greater than 2 D in 41% of eyes. Mean IOL power implanted was 29.9 D (range, 11.5-40.0 D); most eyes (88%) implanted with an IOL of 30.0 D or greater had less postoperative hyperopia than planned. Multivariate analysis revealed that only short axial length (<18 mm) was significant for higher PE.
  
  
  CONCLUSIONS
  Short axial length correlates with higher PE after IOL placement in infants. Less hyperopia than anticipated occurs with axial lengths of less than 18 mm or high-power IOLs. Application to Clinical Practice Quality A-scans are essential and higher PE is common, with a tendency for less hyperopia than expected.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT00212134.
authors.affiliation: Department of Ophthalmology, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA. deborah.vanderveen@childrens.harvard.edu
authors.forename: Deborah K
authors.initials: DK
authors.lastname: VanderVeen
authors.forename: Azhar
authors.initials: A
authors.lastname: Nizam
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lynn
authors.forename: Erick D
authors.initials: ED
authors.lastname: Bothun
authors.forename: Scott K
authors.initials: SK
authors.lastname: McClatchey
authors.forename: David R
authors.initials: DR
authors.lastname: Weakley
authors.forename: Lindreth G
authors.initials: LG
authors.lastname: DuBois
authors.forename: Scott R
authors.initials: SR
authors.lastname: Lambert
mesh_terms: D002386:Cataract / Q000151:congenital; D002387:Cataract Extraction; D002675:Child, Preschool; D005500:Follow-Up Studies; D006801:Humans; D006956:Hyperopia / Q000517:prevention & control*; D007223:Infant; D019654:Lens Implantation, Intraocular / Q000295:instrumentation / Q000379:methods*; D007910:Lenses, Intraocular; D011183:Postoperative Complications / Q000517:prevention & control*; D011237:Predictive Value of Tests; D012031:Refractometry; D014792:Visual Acuity