title: Accuracy of IOL calculations in children: a comparison of immersion versus contact A-scan biometery.
abstract: OBJECTIVE
  To evaluate the accuracy of pediatric IOL calculations performed under general anesthesia by using immersion A-scan biometry and to compare the results to those obtained using contact A-scan biometry.
  
  
  METHODS
  A retrospective review of 203 consecutive cases of pediatric cataract extraction with primary IOL implantation within the capsular bag; mean patient age was 5.52 +/- 4.19 years (range, 18 days to 18 years). Axial length measurements were performed with the contact A-scan biometry in 138 eyes, whereas immersion technique biometry was used in the remaining consecutive 65 eyes. Preoperative predictive target refraction was compared with the refractive result obtained at the 2-month postoperative visit.
  
  
  RESULTS
  The mean of the absolute value lens prediction error for all eyes was 1.08 +/- 0.93 D from the desired postoperative refractive result. Lens prediction error for the contact A-scan subgroup was 1.11 +/- 0.90 D, whereas the immersion A-scan subgroup was less at 1.03 +/- 0.98 D. This result was not statistically significant (p = 0.6442). Statistically significant correlations were found between increased lens prediction error and age at time of surgery or corneal curvature.
  
  
  CONCLUSIONS
  This retrospective, noncomparative pilot study showed no significant difference in IOL prediction error when comparing the postoperative refractive results obtained with immersion versus contact A-scan biometry in pediatric IOL calculations.
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
authors.forename: Itay
authors.initials: I
authors.lastname: Ben-Zion
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Neely
authors.forename: David A
authors.initials: DA
authors.lastname: Plager
authors.forename: Susan
authors.initials: S
authors.lastname: Ofner
authors.forename: Derek T
authors.initials: DT
authors.lastname: Sprunger
authors.forename: Gavin J
authors.initials: GJ
authors.lastname: Roberts
mesh_terms: D000293:Adolescent; D001699:Biometry / Q000379:methods*; D002387:Cataract Extraction; D002648:Child; D002675:Child, Preschool; D005123:Eye / Q000000981:diagnostic imaging*; D006801:Humans; D007101:Immersion; D007223:Infant; D007231:Infant, Newborn; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008962:Models, Theoretical; D010865:Pilot Projects; D011184:Postoperative Period; D011237:Predictive Value of Tests; D012029:Refraction, Ocular; D012189:Retrospective Studies; D014463:Ultrasonography / Q000379:methods / Q000592:standards