Imaging of the anterior chamber by ultrasound biomicroscopy before and after cataract surgery in eyes with primary angle closure glaucoma

Objective:To observe the changes in the anterior chamber before and after cataract surgery by ultrasound biomicroscopy (UBM) in eyes with primary angle closure glaucoma. Methods: Ultrasound biomicroscopy was used for anterior chamber imaging in 78 eyes of 50 patients with primary angle closure glaucoma before and 1 month after cataract phacoemulsification and intraocular lens implantation. And the intraocular pressures were recorded at the same time. Results: UBM allowed the imaging of the entire anterior eye segment. In the images, the differences between iris thickness (IT), iris zonule distance (IZD) and iris lens angle (θ2) before and after the operation were statistically insignificant. After the operation, marked increases were observed in the anterior chamber depth (ACD), angle opening distance at 500 μm from the scleral spur (AOD500), trabecular iris angle (θ1) and trabecular ciliary process distance (TCPD), with statistically very significant differences from preoperation (P 0.01). Scleral ciliary body angle (θ3) was also increased (P 0.05). The intraocular pressures were normal after the withdrawal of medication postoperatively. Visual acuity was improved in all the patients after the operation. Conclusion: Primary angle closure glaucoma can be successfully managed by cataract phacoemulsification, which, at the early stage of the disease, can deepen the anterior chamber, widen the chamber angle and reopen the trabeculae. UBM is very helpful to the operation by providing rapid images of the anterior eye segment.