title: Biometry of anterior segment of human eye on both horizontal and vertical meridians during accommodation imaged with extended scan depth optical coherence tomography.
abstract: OBJECTIVE
  To determine the biometry of anterior segment dimensions of the human eye on both horizontal and vertical meridians with extended scan depth optical coherence tomography (OCT) during accommodation.
  
  
  METHODS
  Twenty pre-presbyopic volunteers, aged between 24 and 30, were recruited. The ocular anterior segment of each subject was imaged using an extended scan depth OCT under non- and 3.0 diopters (D) of accommodative demands on both horizontal and vertical meridians. All the images were analyzed to yield the following parameters: pupil diameter (PD), anterior chamber depth (ACD), anterior and posterior surface curvatures of the crystalline lens (ASC and PSC) and the lens thickness (LT). Two consecutive measurements were performed to assess the repeatability and reproducibility of this OCT. They were evaluated by calculating the within-subject standard deviation (SD), a paired t-test, intra-class correlation coefficients (ICC) and the coefficient of repeatability/reproducibility (CoR).
  
  
  RESULTS
  There were no significant differences between two consecutive measurements on either horizontal or vertical meridians under both two different accommodative statuses (P>0.05). The ICC for all parameters ranged from 0.775 to 0.998, except for the PSC (0.550) on the horizontal meridian under the non-accommodative status. In addition, the CoR for most of the parameters were excellent (0.004% to 4.89%). In all the parameters, only PD and PSC were found different between the horizontal and vertical meridians under both accommodative statuses (P<0.05). PD, ACD, ASC and PSC under accommodative status were significantly smaller than those under the non-accommodative status, except that the PSC at the vertical meridian did not change. In addition, LT was significantly increased when accommodation.
  
  
  CONCLUSIONS
  The extended scan depth OCT successfully measured the dimensions of the anterior eye during accommodation with good repeatability and reproducibility on both horizontal and vertical meridians. The asymmetry of lens posterior surface and oval-shaped pupil were found during accommodation.
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Leng
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Chen
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Meixiao
authors.initials: M
authors.lastname: Shen
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Qingkai
authors.initials: Q
authors.lastname: Ma
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Lin
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Dexi
authors.initials: D
authors.lastname: Zhu
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Qu
authors.affiliation: School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Lu
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D000867:Anterior Chamber / Q000033:anatomy & histology* / Q000502:physiology; D001699:Biometry / Q000379:methods; D005260:Female; D006801:Humans; D007908:Lens, Crystalline / Q000033:anatomy & histology* / Q000502:physiology; D008297:Male; D009799:Ocular Physiological Phenomena; D011305:Presbyopia; D011680:Pupil / Q000502:physiology*; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence