title: The diurnal variation pattern of choroidal thickness in macular region of young healthy female individuals using spectral domain optical coherence tomography.
abstract: OBJECTIVE
  To investigate the pattern of diurnal variations of choroidal thickness of macular region of healthyindividuals.
  
  
  METHODS
  A prospective study of 32 healthy female subjects was conducted. Each subject underwent 1) a questionnaire on daily schedule, 2) the Pittsburgh Sleep Quality Index questionnaire (PSQI), and 3) ocular examinations including an eye dominance test, fundus photography, and sequential optical coherence tomography (OCT) imaging, on two separate days at five fixed 3h time intervals. Choroidal thickness was measured by two masked graders.
  
  
  RESULTS
  A significant diurnal variation of choriodal thickness at fovea (P<0.001), at 500 µm nasal (P<0.001), temporal to fovea (P=0.01) or 1500 µm nasal to fovea (P=0.001) was observed. The median choroidal thickness peaked at 11:00 at fovea (P=0.01), at 500 µm nasal (P=0.009) and temporal (P=0.03) to fovea. The median amplitude of foveal choroidal thickness was 20.5 µm (13, 31) and 20.0 µm (12.5, 28.2) for the first and second series of measurements, respectively. The greater amplitude of foveal choroidal thickness was associated with thickner initial foveal choroidal thickness [0.05 (0.03, 0.08), P=0.01], dominant eye [10.51 (4.02, 14.60), P=0.04] in the multivariate linear regression.
  
  
  CONCLUSIONS
  Our data show a significant diurnal variation of the choroidal thickness at fovea, at 500 µm nasal and temporal to fovea and 1500 µm nasal to fovea. Thicker initial foveal choroidal thickness and being dominant eye may influence the amplitude of foveal choroidal thickness.
authors.affiliation: Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory,Beijing 100730, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China.
authors.forename: Xiu-Fen
authors.initials: XF
authors.lastname: Yang
authors.affiliation: Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory,Beijing 100730, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Jiao
authors.affiliation: Department of Mathematics and Computer Science, Faculty of Science and Technology, Prince of Songkla University, Pattani Campus, MuangPattani90112, Thailand.
authors.forename: Apiradee
authors.initials: A
authors.lastname: Lim
authors.affiliation: Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory,Beijing 100730, China.
authors.forename: Xue-Tao
authors.initials: XT
authors.lastname: Ren
authors.affiliation: Sekwa Institute of Medical Science, Beijing 100088, China.
authors.forename: Torkel
authors.initials: T
authors.lastname: Snellingen
authors.affiliation: Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory,Beijing 100730, China.
authors.forename: Ning-Pu
authors.initials: NP
authors.lastname: Liu
keywords: choroidal thickness; diurnal variation; optical coherence tomography