title: Determinants of pupil diameters and pupil dynamics in an adult Chinese population.
abstract: BACKGROUND
  To investigate the determinants of pupil diameter (PD), amplitude of pupil diameter change (PD-change) and speed of pupil constriction (SPC) using video anterior segment optical coherence tomography (AS-OCT) in a population-based sample of Chinese adults.
  
  
  METHODS
  Chinese adults aged 40 to 80 years who were free from glaucoma were consecutively recruited from the population-based Singapore Chinese Eye Study. The SPC was measured by AS-OCT videography. Univariate and multivariate analyses were performed to examine the effects of demographic and ocular biometric factors (e.g., axial length [AL], anterior chamber depth [ACD], baseline PD, iris thickness at the area of the dilator muscle [ITDMR], iris area [IA], and iris bowing [IB]) on SPC, PD, and PD-change.
  
  
  RESULTS
  A total of 266/302 (89.5 %) AS-OCT videos of eligible eyes were available for analysis. Among these subjects, 64.3 % were women, and the mean age (± standard deviation [SD]) was 56 ± 8.3 years. SPC was not associated with sex. In multiple regression analyses, SPC was independently associated with baseline PD (β = 0.116, p = 0.006). Baseline PD was independently associated with ACD (β = 0.341, p < 0.001), TISA 500 (β = -4.513, p < 0.001), IA (β = -2.796, p < 0.001), and ITDMR (β = 6.573, p < 0.001). PD-change was independently associated with ACD (β = 0.256, p < 0.001), IA (β = -1.507, p < 0.001), IB (β = 0.630, p = 0.011), and ITDMR (β = 3.124, p < 0.001).
  
  
  CONCLUSIONS
  Among normal eyes in an adult Chinese population, SPC was associated with larger baseline PD. Larger baseline PD and greater PD change form dark to light were associated with greater ACD, with smaller IA and thicker ITDMR.
authors.affiliation: Singapore Eye Research Institute & Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore.|Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, 1E Kent Ridge Road NUHS Tower Block, Level 11, Singapore, 119228, Singapore.|Joint Shantou International Eye Center of Shantou University and Chinese University of Hong Kong, Dong Xia North Road, Shantou, 515041, Guangdong Province, China.
authors.forename: Ce
authors.initials: C
authors.lastname: Zheng
authors.affiliation: Singapore Eye Research Institute & Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore.
authors.forename: John Mark S
authors.initials: JM
authors.lastname: de Leon
authors.affiliation: Singapore Eye Research Institute & Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore.|Duke-NUS Graduate Medical School, National University of Singapore, 8 College Road, Singapore, 169857, Singapore.
authors.forename: Carol Y
authors.initials: CY
authors.lastname: Cheung
authors.affiliation: Singapore Eye Research Institute & Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore.
authors.forename: Arun K
authors.initials: AK
authors.lastname: Narayanaswamy
authors.affiliation: Department of Electrical & Computer Engineering, National University of Singapore, 1E Kent Ridge Road NUHS Tower Block, Level 11, Singapore, 119228, Singapore.
authors.forename: Sim-Heng
authors.initials: SH
authors.lastname: Ong
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, 1E Kent Ridge Road NUHS Tower Block, Level 11, Singapore, 119228, Singapore.
authors.forename: Clement W
authors.initials: CW
authors.lastname: Tan
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, 1E Kent Ridge Road NUHS Tower Block, Level 11, Singapore, 119228, Singapore.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Chew
authors.affiliation: Singapore Eye Research Institute & Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore.
authors.forename: Shamira A
authors.initials: SA
authors.lastname: Perera
authors.affiliation: Singapore Eye Research Institute & Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore.|Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, 1E Kent Ridge Road NUHS Tower Block, Level 11, Singapore, 119228, Singapore.|Duke-NUS Graduate Medical School, National University of Singapore, 8 College Road, Singapore, 169857, Singapore.
authors.forename: Tien Y
authors.initials: TY
authors.lastname: Wong
authors.affiliation: Singapore Eye Research Institute & Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore. aung.tin@snec.com.sg.|Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, 1E Kent Ridge Road NUHS Tower Block, Level 11, Singapore, 119228, Singapore. aung.tin@snec.com.sg.|Duke-NUS Graduate Medical School, National University of Singapore, 8 College Road, Singapore, 169857, Singapore. aung.tin@snec.com.sg.
authors.forename: Tin
authors.initials: T
authors.lastname: Aung
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000208:ethnology*; D055253:Color Vision; D005260:Female; D006801:Humans; D007498:Iris / Q000033:anatomy & histology*; D008297:Male; D055255:Mesopic Vision; D008875:Middle Aged; D015588:Observer Variation; D011680:Pupil / Q000502:physiology*; D015203:Reproducibility of Results; D012846:Singapore / Q000453:epidemiology; D041623:Tomography, Optical Coherence; D014741:Video Recording
keywords: Angle-closure glaucoma; Iris constriction; Lens; Pupil; Speed of iris
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