Abstract
Abstract: :
Purpose: There have been several case reports indicating that anterior inclination of the ciliary process caused shallow anterior chamber and angle-closure glaucoma in patients with some ocular pathologies, such as Harada disease, plateau iris, and post-scleral buckling surgery. The exact mechanisms of shallow anterior chamber in these conditions, however, remain unknown largely due to the lack of quantitative study on the relation between ciliary process inclination and anterior chamber depth. Methods: Eyes with persistent or transient shallow chamber were examined. Subjects were 13 eyes with aniridia, 6 eyes with Harada disease, 5 eyes after scleral buckling, 2 eyes with malignant glaucoma, and 1 eye with expulsive hemorrhage after filtering surgery. Ninety eyes of 90 subjects served as normal controls. We measured the inclination degree of ciliary process in four directions and the central anterior chamber depth using the ultrasound biomicroscopy (UBM) with 30MHz transducer. The inclination degree of ciliary body was defined as the angle between the axis of ciliary process and the line tangential to the sclera. Results: Eyes with shallow chamber showed significantly smaller inclination of the ciliary body than the normal controls (30.1 ± 6.26 vs. 41.3 ± 6.08 degrees, p<0.0001, unpaired t-test). Anterior chamber was significantly shallower in the pathology group (2.03 ± 0.67 vs. 2.79 ± 0.34mm, p<0.0001). In the normal group, there was a positive correlation between the inclination degree of ciliary process and anterior chamber depth (Pearson r=0.333, p<0.005). The eyes with shallow anterior chamber also showed a positive correlation between the inclination degree of ciliary process and anterior chamber depth (r=0.391, p<0.05). In eyes with Harada disease and those after scleral buckling, transient ciliary body edema caused forward inclination of the ciliary body and shallow anterior chamber, which subsided with the improvement of ciliary body edema. In malignant glaucoma and expulsive hemorrhage, the ciliary process inclined anteriorly because anterior vitreous pressed the ciliary body. In aniridia, the ciliary processes were situated anteriorly because of ciliary body hypoplasia. Conclusions: The forward inclination of the ciliary process significantly influences anterior chamber depth not only in the eyes with shallow chamber but also in normal subjects. At least three different mechanisms may exist in the pathological shallowing of the anterior chamber.
Keywords: ciliary body • anterior chamber • imaging methods (CT, FA, ICG, MRI, OCT, RTA, S