Quantitative Measurements of the Ciliary Body in Eyes With Acute Primary-Angle Closure

Purpose: To compare the structural differences of the ciliary body in patients with acute primary-angle closure (APAC) and normal subjects.

Methods: Forty-four patients with APAC in one eye and 25 eyes from 25 age-matched normal subjects were consecutively recruited. A-scan ultrasound and ultrasound biomicroscopy (UBM) measurements were performed. Ciliary body parameters including maximum ciliary body thickness (CBTmax), ciliary body thickness at point of the scleral spur (CBT0) and 1000 μm from the scleral spur (CBT1000), anterior placement of ciliary body (APCB), and trabecular-ciliary process angle (TCA), as well as biometric measurements, were measured.

Results: Average CBTmax was 0.894 ± 0.114, 0.967 ± 0.110, and 1.053 ± 0.103 mm in eyes with APAC, their fellow eyes, and normal eyes, respectively. Average CBT1000 was 0.616 ± 0.111, 0.631 ± 0.088, and 0.842 ± 0.118 mm, respectively. Average TCA was 48.10 ± 13.26°, 50.60 ± 9.08°, and 87.11 ± 20.71°, respectively. CBTmax and CBT0 were thinner in eyes with APAC compared with their fellow eyes (P = 0.002, P < 0.001). In addition, CBTmax, CBT1000, and TCA were smaller whereas APCB was larger in the fellow eyes of APAC patients compared with normal eyes (P = 0.002, P < 0.001, P < 0.001, P < 0.001). The anterior chamber depth (ACD) was smaller whereas lens thickness (LT) was larger in eyes with APAC compared with their fellow eyes (P < 0.001, P = 0.036). Smaller ACD and axial length and larger LT and lens vault were found in the fellow eyes of APAC patients compared with normal eyes (P < 0.001, P < 0.001, P = 0.015, P = 0.001).

Conclusions: Ciliary bodies were thinner and more anteriorly rotated in eyes with APAC as well as in their fellow eyes. Further studies are needed to elucidate the relationship between ciliary body parameters and mechanism of APAC.