title: Agreement and reproducibility of contact and immersion techniques for axial length measurement and intraocular lens power calculation.
abstract: OBJECTIVE
  To investigate the agreement and reproducibility of contact and immersion ultrasound biometry in an axial length measurement and intraocular lens power calculation.
  
  
  METHODS
  Prospective cross-sectional study.
  
  
  METHODS
  Axial length was measured in 198 cataract patients using both contact and immersion techniques, randomly assigned to two measurers, one with more experience than the other Both techniques were repeated by each measurer. The mean difference of both techniques was calculated for the difference of the intraocular lens power.
  
  
  RESULTS
  The respective mean differences of both techniques for the first and the second measurers were 0.03 and 0.07 mm. The repeatability coefficient was two-fold for the contact but was similar for the immersion technique. The respective difference of the intraocular lens power of both measurers was 1.15 and 1.65 diopters (D). A statistically significant agreement was noted between both techniques. The reproducibility of both techniques was similar when performed by an experienced measurer however, the less experienced measurer had greater reproducibility with the immersion technique.
  
  
  CONCLUSIONS
  The difference in the intraocular lens power from both techniques may have clinical significance; hence, the immersion technique should be considered, particularly for less-experienced measurer.
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. Kitthisak@hotmail.com
authors.forename: Kitthisak
authors.initials: K
authors.lastname: Kitthaweesin
authors.forename: Warataporn
authors.initials: W
authors.lastname: Mungsing
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D001699:Biometry / Q000379:methods*; D016001:Confidence Intervals; D003315:Cornea / Q000033:anatomy & histology*; D003430:Cross-Sectional Studies; D004867:Equipment Design; D005260:Female; D006801:Humans; D007101:Immersion; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D013223:Statistics as Topic