title: Associations between choroidal thickness, axial length and spherical equivalent in a paediatric population.
abstract: BACKGROUND
  The aim was to compare the choroidal thickness (ChT) of myopic children's eyes with that of emmetropes to determine whether there are associations between ChT, axial length and spherical equivalent (SE) in a paediatric population.
  
  
  METHODS
  A total of 117 eyes of 117 children including 53 myopic eyes (myopic group) and 64 emmetropic eyes (emmetropic group) were enrolled in this cross-sectional comparative study. ChT was analysed by using the HD 5 Line Raster scan protocol of spectral domain enhanced depth imaging optical coherence tomography. Subfoveal ChT was measured manually as the distance between the retinal pigment epithelium and the chorioscleral border and three additional measurements were carried out every 750 μm temporal (T1, T2 and T3) and nasal (N1, N2 and N3) to the fovea.
  
  
  RESULTS
  The mean age was 11.7 ± 2.7 years (range five to 17 years) in the myopic group and 10.9 ± 3.4 years (range 5 to 17 years) in the emmetropic group. There were no significant differences between the groups concerning age and sex (both p > 0.05). The myopic eyes had significantly thinner subfoveal, T1, T2, T3, N1, N2, N3 and average choroid than the emmetropic eyes (all p < 0.05). In addition, correlation analyses among all the study subjects showed that all subfoveal, T1, T2, T3, N1, N2, N3 and average ChT had negative correlations with axial length and positive correlations with the SE.
  
  
  CONCLUSIONS
  The present study showed that the myopic children's eyes had significantly thinner subfoveal choroid than the emmetropic control eyes. Further, ChT was negatively correlated with axial length and positively correlated with SE in the population that included myopic and emmetropic children.
authors.affiliation: Department of Ophthalmology, Recep Tayyip Erdoğan University Medical School Education and Research Hospital, Rize, Turkey.
authors.forename: Asker
authors.initials: A
authors.lastname: Bulut
authors.affiliation: Department of Ophthalmology, Recep Tayyip Erdoğan University Medical School Education and Research Hospital, Rize, Turkey. veysioner@gmail.com.
authors.forename: Veysi
authors.initials: V
authors.lastname: Öner
authors.affiliation: Department of Ophthalmology, Recep Tayyip Erdoğan University Medical School Education and Research Hospital, Rize, Turkey.
authors.forename: Şeyma
authors.initials: Ş
authors.lastname: Büyüktarakçı
authors.affiliation: Department of Ophthalmology, Recep Tayyip Erdoğan University Medical School Education and Research Hospital, Rize, Turkey.
authors.forename: Muhammet
authors.initials: M
authors.lastname: Kaim
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002829:Choroid / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000473:pathology*; D055213:Retinal Pigment Epithelium / Q000473:pathology; D041623:Tomography, Optical Coherence
keywords: axial length; children; choroidal thickness; enhanced depth imaging; myopia; refractive error