Ultrasound biomicroscopic configurations of the anterior ocular segment in a population-based study the Kumejima Study.
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.
Henzan
Ichiko Medoruma
IM
Department of Ophthalmology, University of the Ryukyus, Graduate School of Medicine, Okinawa, Japan.
Tomidokoro
Atsuo
A
Uejo
Chiharu
C
Sakai
Hiroshi
H
Sawaguchi
Shoichi
S
Iwase
Aiko
A
Araie
Makoto
M
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