title: Correlations between refractive error and biometric parameters in human eyes using the LenStar 900.
abstract: OBJECTIVE
  To investigate the relationship between refractive error and ocular biometry in healthy subjects using a new optical low coherence reflectometry device.
  
  
  METHODS
  Biometric measurements were obtained with a LenStar LS 900 (Haag Streit, Switzerland) on one eye of 70 phakic subjects (mean ± SD age; 29 ± 9 years). Forty myopes and 30 non-myopes (best sphere range -9.63 D to +0.63 D) were included. Outcome measures were compared for the two groups using one way between groups ANOVA. These included; keratometry, central corneal thickness, iris width, anterior chamber depth, pupil diameter, lens thickness, axial length and retinal thickness. No mydriatic or cycloplegic agents were used.
  
  
  RESULTS
  There were significant differences between groups for keratometry readings (p = 0.021 and p = 0.038 for steep and flat k readings respectively), anterior chamber depth (p = 0.001), lens thickness (p = 0.026) and axial length (p<0.001). As expected significant correlations were found between spherical equivalent power and axial length (Pearson product-moment correlation r = -0.75, p<0.001) and between spherical equivalent power and anterior chamber depth (r = -0.29, p = 0.018). Anterior chamber depth and pupil diameter decreased with age (r = -0.429, p<0.001 and r = -0.386, p = 0.001 respectively) whereas lens thickness increased with age (r = 0.618, p < 0.001).
  
  
  CONCLUSIONS
  Our data showed significant differences between myopes and non-myopes for the key biometric parameters assessed and provides information about the relationships between these biometric parameters and age. The results, coupled with a unique ability to image and analyse the ocular structures non-invasively make the LenStar a promising new instrument for ocular evaluation in research and clinical practice.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Manchester, UK. Clare.odonnell@manchester.ac.uk
authors.forename: Clare
authors.initials: C
authors.lastname: O'Donnell
authors.forename: Andreas
authors.initials: A
authors.lastname: Hartwig
authors.forename: Hema
authors.initials: H
authors.lastname: Radhakrishnan
mesh_terms: D000328:Adult; D001699:Biometry / Q000379:methods*; D003315:Cornea / Q000473:pathology* / Q000503:physiopathology*; D019781:Corneal Topography / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D012030:Refractive Errors / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D041623:Tomography, Optical Coherence / Q000295:instrumentation*