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I. Henzan, C. Uejo, H. Sakai, S. Sawaguchi, A. Iwase, A. Tomidokoro, M. Araie; Configurations of Anterior Chamber Angle Evaluated With Ultrasound Biomicroscopy in a Population-Based Study: Kumejima Study. Invest. Ophthalmol. Vis. Sci. 2009;50(13):432.
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© ARVO (1962-2015); The Authors (2016-present)
To quantitatively evaluate the configurations of the anterior chamber angle evaluated with ultrasound biomicroscopy (UBM) in a randomly sampled population.
All 4632 residents aged 40 years or older of Kumejima Island, a southern rural island of Japan, were invited to participate in an epidemiological survey on glaucoma and ocular conditions. Ten percent of the residents (461 subjects) were randomly selected as candidates for UBM testing. UBM was performed under light and dark conditions in the superior, inferior, temporal and nasal quadrants of his/her right eyes only. Parameters to quantify angle opening, location of the ciliary body, thickness of the iris and anterior bowing of the iris were determined in UBM images by a single masked examiner.
Sixty-six subjects were excluded because of history of intraocular surgeries or ocular traumas in his/her right eyes, resulting in that 395 were eligible. Reliable UBM data were obtained in 301 (76.2%) of the 395 eligible subjects. Parameters of angle opening, location of ciliary body and iris thickness significantly varied among the four quadrants (P>0.15). The iris was thicker in dark than in light in all quadrants (P<0.01). Anterior bowing of back surface of the iris was not significantly different among the four quadrants (P=0.72); and was more evident in dark than in light in the superior, inferior and nasal quadrants (P<0.01).
Configurations of the anterior chamber angle evaluated by UBM was first determined in a population randomly sampled from whole regional residents. The angle opening, location of the ciliary body and iris thickness were different among the four quadrants. Angle opening, anterior bowing of the iris, and iris thickness were significantly influenced by light conditions, while location of the ciliary body was not.
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