Ultrasound biomicroscopic changes after laser iridotomy or trabeculectomy in angle-closure glaucoma

This study was performed to demonstrate the ultrasound, biomicroscopic and dimensional changes of angle structure after laser iridotomy (LI) and primary trabeculectomy (PT) in primary angle-closure glaucoma (PACG). Angle-opening distance at a point 500 m from the scleral spur (AOD500), trabecular-iris angle (theta1), trabecular ciliary process distance (TCPD), ciliary process-iris angle (CPI), iris thickness (ID1, ID3), length of iris-lens contact distance (ILCD) and anterior chamber depth (ACD) were assessed before and after each procedure. Thirteen patients with LI and 16 with PT were prospectively enrolled. There were statistically significant increases in AOD500, theta1, and ILCD in both groups. CPI was decreased in both groups. ACD, TCPD, and iris thickness were not changed significantly. The changes in angle configuration after LI or PT may result more from alterations in aqueous pressure gradients across the iris and the changes of configuration were greater in the iris roots without rotation of ciliary body. However, we didn't find any significant differences in the changes of parameters between the two procedures.