title: Macular choroidal thicknesses in healthy adults--relationship with ocular and demographic factors.
abstract: OBJECTIVE
  To determine the differences in choroidal thickness (CT) among different groups of refractive errors and axial lengths, and to describe the rates of change of CT with ocular and demographic factors in various regions of the macula.
  
  
  METHODS
  Prospective cohort study of 150 healthy volunteers. Spectral-domain optical coherence tomography was performed on both eyes using a standardized imaging protocol. Manual grading of the choroidal boundaries was independently performed by trained graders to determine Early Treatment Diabetic Retinopathy Study (ETDRS) subfield choroidal thickness. Multiple linear regression analyses were performed to determine the effects of spherical equivalent, axial length and age on choroidal thickness in each subfield.
  
  
  RESULTS
  The mean central subfield CT was 324.9 μm (range, 123-566 μm) and varied significantly with both spherical equivalent (P < 0.001) and axial length (P < 0.001), but not age or sex. On multiple linear regression analysis using spherical equivalent, the coefficients were 20.0 for the central subfield, ranged from 16.9 to 19.9 for the inner subfields, and decreased to 13.9 to 16.2 for the outer subfields. Performing regression analysis using axial length, the coefficients were -36.4 for the central subfield, -30.5 to -34.5 for the inner subfields, and -24.6 to -27.3 for the outer subfields.
  
  
  CONCLUSIONS
  Choroidal thickness varies significantly with spherical equivalent and axial length in all regions of the macula, but exhibits different rates of change among different subfields. The rates of change were greater in the central and inner subfields compared with the outer subfields.
authors.affiliation: National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore Fundus Image Reading Center, National Healthcare Group Eye Institute, Singapore.
authors.forename: Colin S H
authors.initials: CS
authors.lastname: Tan
authors.affiliation: National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore.
authors.forename: Kai Xiong
authors.initials: KX
authors.lastname: Cheong
mesh_terms: D000328:Adult; D058452:Axial Length, Eye; D002829:Choroid / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D064368:Healthy Volunteers; D006801:Humans; D006984:Hypertrophy; D008266:Macula Lutea / Q000473:pathology*; D008297:Male; D015995:Prevalence; D011446:Prospective Studies; D012030:Refractive Errors / Q000453:epidemiology / Q000473:pathology*; D012846:Singapore / Q000453:epidemiology; D041623:Tomography, Optical Coherence / Q000379:methods*; D055815:Young Adult
keywords: choroidal thickness; macula; ocular and demographic factors; optical coherence tomography; refractive error