title: Ultrasound biomicroscopic configurations of the anterior ocular segment in a population-based study the Kumejima Study.
abstract: OBJECTIVE
  To characterize quantitatively the configuration of the anterior ocular segment with ultrasound biomicroscopy (UBM) in a population-based setting.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Ten percent of 4632 residents aged > or =40 years of Kumejima, an island off southwest Japan, were randomly selected.
  
  
  METHODS
  We performed UBM under light and dark conditions in the 4 quadrants of the right eyes. The anatomic landmarks on the anterior ocular segment UBM images were identified by 1 examiner to quantify the peripheral anterior chamber depth (ACD), location of the ciliary body, and iris thickness.
  
  
  METHODS
  Angle-opening distance at 250 and 500 microm from the scleral spur (AOD250, AOD500), trabecular-iris angle (TIA), trabecular-ciliary process distance (TCPD), thickness of the iris (ID), trabecular-anterior iris surface angle (TAIA), trabecular-posterior iris surface angle (TPIA), trabecular-ciliary angle (TCA), and thickness of iris measured at 1000, 2000, and 3000 microm (IT1000, IT2000 and IT3000).
  
  
  RESULTS
  The AOD500 averaged 0.267+/-0.138 (mean +/- standard deviation) and 0.202+/-0.116 mm under light and dark conditions, respectively; TIA 22.2+/-10.0 and 17.0+/-8.9 degrees; TCPD 0.755+/-0.165 and 0.748+/-0.152 mm; and ID 0.412+/-0.053 and 0.457+/-0.062 mm. The peripheral ACD was deepest temporally, then nasally, then inferiorly, and then superiorly (P<0.05, post hoc test). The position of the ciliary body was deepest nasally, then temporally, then inferiorly, and then superiorly (P<0.05). Iris thickness did not differ significantly among the quadrants. Older subjects had a shallower peripheral ACD, more anteriorly located ciliary body, and thinner iris (analysis of covariance, P<0.015). The peripheral ACD was deeper and the ciliary body was located more deeply in men than women (P<0.05), although no intergender differences in iris thickness were seen (P>0.1). Hyperopia, short axial length, and shallow central ACD were significantly correlated with shallower peripheral ACD, anteriorly located ciliary body, and thinner iris (P<0.05). Elevated intraocular pressure was associated with a shallow peripheral ACD (P< or =0.043).
  
  
  CONCLUSIONS
  There are significant associations of the peripheral ACD, location of the ciliary body, and iris thickness with age, gender, refractive error, axial length, and intraocular pressure.
authors.affiliation: Department of Ophthalmology, University of the Ryukyus, Graduate School of Medicine, Okinawa, Japan.
authors.forename: Ichiko Medoruma
authors.initials: IM
authors.lastname: Henzan
authors.forename: Atsuo
authors.initials: A
authors.lastname: Tomidokoro
authors.forename: Chiharu
authors.initials: C
authors.lastname: Uejo
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakai
authors.forename: Shoichi
authors.initials: S
authors.lastname: Sawaguchi
authors.forename: Aiko
authors.initials: A
authors.lastname: Iwase
authors.forename: Makoto
authors.initials: M
authors.lastname: Araie
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber / Q000000981:diagnostic imaging*; D002924:Ciliary Body / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000000981:diagnostic imaging*; D006801:Humans; D006956:Hyperopia / Q000175:diagnosis*; D007429:Intraocular Pressure; D007498:Iris / Q000000981:diagnostic imaging*; D007564:Japan; D008297:Male; D033401:Microscopy, Acoustic; D008875:Middle Aged; D012307:Risk Factors; D012424:Rural Population; D012737:Sex Factors