title: Choroidal thickness in myopic and nonmyopic children assessed with enhanced depth imaging optical coherence tomography.
abstract: OBJECTIVE
  We examined choroidal thickness (ChT) and its topographic variation across the posterior pole in myopic and nonmyopic children.
  
  
  METHODS
  A total of 104 children aged 10 to 15 years (mean age, 13.1 ± 1.4 years) had ChT measured using enhanced depth imaging optical coherence tomography (OCT). Of these children 40 were myopic (mean spherical equivalent, -2.4 ± 1.5 diopters [D]) and 63 were nonmyopic (mean, +0.3 ± 0.3 D). Two series of 6 radial OCT line scans centered on the fovea were assessed for each child. Subfoveal ChT and ChT across a series of parafoveal zones over the central 6 mm of the posterior pole were determined through manual image segmentation.
  
  
  RESULTS
  Subfoveal ChT was significantly thinner in myopes (mean, 303 ± 79 μm) compared to nonmyopes (mean, 359 ± 77 μm, P < 0.0001). Multiple regression analysis revealed refractive error (r = 0.39, P < 0.001) and age (r = 0.21, P = 0.02) were associated positively with subfoveal ChT. Also, ChT exhibited significant topographic variations, with the choroid being thicker in more central regions. The thinnest choroid was observed typically in nasal (mean, 286 ± 77 μm) and inferior-nasal (306 ± 79 μm) locations, and the thickest in superior (346 ± 79 μm) and superior-temporal (341 ± 74 μm) locations. The difference in ChT between myopic and nonmyopic children was significantly greater in central foveal regions compared to more peripheral regions (>3 mm diameter, P < 0.001).
  
  
  CONCLUSIONS
  Myopic children have significantly thinner choroids compared to nonmyopic children of similar age, particularly in central foveal regions. The magnitude of difference in choroidal thickness associated with myopia appears greater than would be predicted by a simple passive choroidal thinning with axial elongation.
authors.affiliation: Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Queensland, Australia.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Read
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Collins
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Vincent
authors.forename: David
authors.initials: D
authors.lastname: Alonso-Caneiro
mesh_terms: D000293:Adolescent; D002648:Child; D002829:Choroid / Q000033:anatomy & histology / Q000473:pathology*; D005260:Female; D005584:Fovea Centralis; D006801:Humans; D008297:Male; D009216:Myopia / Q000150:complications*; D015588:Observer Variation; D009929:Organ Size; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods / Q000592:standards
keywords: choroid; myopia; pediatric; refractive error