title: Multicenter study of optical low-coherence interferometry and partial-coherence interferometry optical biometers with patients from the United States and China.
abstract: OBJECTIVE
  To evaluate the agreement between the measurements provided by a new optical biometer, the Aladdin, based on optical low-coherence interferometry (OLCI), and those provided by the most commonly used optical biometer (IOLMaster 500), based on partial-coherence interferometry (PCI).
  
  
  METHODS
  Multicenter clinical trial.
  
  
  METHODS
  Prospective evaluation of diagnostic test.
  
  
  METHODS
  In this study, 2 samples of adult patients were enrolled, 1 in the United States and the other in China. The U.S. group included a sample of consecutive patients scheduled for cataract surgery. The China group included a sample of healthy subjects with no cataracts. In both cases, only 1 eye of each patient was analyzed. Axial length (AL), corneal power (in diopters [D]) (K), anterior chamber depth (ACD) (corneal epithelium to lens), and corneal astigmatism were measured. All values were analyzed using a paired t test, the Pearson product-moment correlation coefficient (r), and Bland-Altman plots.
  
  
  RESULTS
  In the U.S. and China groups, the OLCI mean AL values did not show a statistically significant difference from PCI values and showed excellent agreement and correlation. On the contrary, OLCI measured a lower mean K (-0.14 D) and a deeper ACD measurements (U.S. +0.16 mm and China +0.05 mm). These differences were statistically significant (P < .0001). Vector analysis did not show a statistically significant difference in astigmatism measurements.
  
  
  CONCLUSIONS
  Agreement between OLCI and PCI was good. However, the small but statistically significant differences in K and ACD measurements make constant optimization necessary when calculating the intraocular lens power using theoretical formulas.
  
  
  BACKGROUND
  Dr. Hoffer licenses the registered trademark name Hoffer to Carl Zeiss-Meditec (PCI), Haag-Streit (Lenstar), Movu (Argos), Oculus (Pentacam, AXL), Nidek (AL-Scan), Tomey (OA-2000), Topcon EU Visia Imaging (Aladdin), Ziemer (Galilei G6), and all A-scan biometer manufacturers. Dr. Shammas licenses his formulas to Carl Zeiss-Meditec (PCI), Haag-Streit (Lenstar), Nidek (AL-Scan), and Topcon EU (Visia Imaging) (Aladdin). None of the other authors has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: From Stein Eye Institute (Hoffer), University of California, Los Angeles; St. Mary's Eye Center (Hoffer), Santa Monica, California; Keck School of Medicine (Shammas), Los Angeles, and; Shammas Eye Medical Center (Shammas), Lynwood, California, USA; G.B. Bietti Foundation IRCCS (Savini), Rome, Italy; School of Ophthalmology and Eye Hospital (Huang), Wenzhou Medical University, Wenzhou, China. Electronic address: khoffermd@aol.com.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Hoffer
authors.affiliation: From Stein Eye Institute (Hoffer), University of California, Los Angeles; St. Mary's Eye Center (Hoffer), Santa Monica, California; Keck School of Medicine (Shammas), Los Angeles, and; Shammas Eye Medical Center (Shammas), Lynwood, California, USA; G.B. Bietti Foundation IRCCS (Savini), Rome, Italy; School of Ophthalmology and Eye Hospital (Huang), Wenzhou Medical University, Wenzhou, China.
authors.forename: H John
authors.initials: HJ
authors.lastname: Shammas
authors.affiliation: From Stein Eye Institute (Hoffer), University of California, Los Angeles; St. Mary's Eye Center (Hoffer), Santa Monica, California; Keck School of Medicine (Shammas), Los Angeles, and; Shammas Eye Medical Center (Shammas), Lynwood, California, USA; G.B. Bietti Foundation IRCCS (Savini), Rome, Italy; School of Ophthalmology and Eye Hospital (Huang), Wenzhou Medical University, Wenzhou, China.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Savini
authors.affiliation: From Stein Eye Institute (Hoffer), University of California, Los Angeles; St. Mary's Eye Center (Hoffer), Santa Monica, California; Keck School of Medicine (Shammas), Los Angeles, and; Shammas Eye Medical Center (Shammas), Lynwood, California, USA; G.B. Bietti Foundation IRCCS (Savini), Rome, Italy; School of Ophthalmology and Eye Hospital (Huang), Wenzhou Medical University, Wenzhou, China.
authors.forename: Jinhai
authors.initials: J
authors.lastname: Huang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber / Q000473:pathology*; D001251:Astigmatism / Q000175:diagnosis; D058452:Axial Length, Eye / Q000473:pathology*; D001699:Biometry / Q000295:instrumentation*; D002386:Cataract / Q000150:complications / Q000208:ethnology; D002387:Cataract Extraction; D002681:China; D003315:Cornea / Q000473:pathology*; D005006:Ethnicity; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007368:Interferometry / Q000295:instrumentation; D008027:Light; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D014481:United States; D055815:Young Adult