Abstract :
Purpose: To study the morphological changes of the angle structure after laser iridotomy (LI) and primary trabeculectomy (PT) in primary angle-closure glaucoma (PACG) using ultrasound biomicroscopy (UBM).Method: Thirty patients with primary angle-closure glaucoma (PACG) were prospectively enrolled in this study. They were divided into two groups; the first group consisted of 14 patients who had undergone laser iridotomy. The second group consisted of 16 patients who had undergone trabeculectomy surgery. Patients underwent anterior segment evaluation including gonioscopy, disc evaluation with+90D lens, applanation intraocular pressure. Ultrasound biomicroscopy study was performed for each patient before and two weeks after the procedure. Parameters which were assessed included Trabecular-iris angle (TIA) (theta1),Central anterior chamber depth (ACD), Angle-opening distance at a point 500 μm from the scleral spur (AOD500), trabecular ciliary process distance (TCPD), ciliary process-iris angle (CPI), iris thickness (ID 1, ID3) and length of iris-lens contact distance (ILCD).Results: There were statistically significant increases in AOD500, (TIA) 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. However, no significant differences in the changes of parameters between the two procedures had been found except for postoperative CPI (p=0.019), indicating that the degree of iris moving back was less in the PT group than in the LI group.Conclusion: UBM gives an accurate and objective documentation of the changes in the anterior chamber angle morphology induced by an LPI and Primary trabeculectomy in PACG. It was evident that both the LI and PT procedures could improve the pressure gradient between the anterior and posterior chambers, but couldn t improve the lens and ciliary body positions.
