A Prosective Evaluation Of Changes In Anterior Segment Morphology After Laser Iridotomy.

Purpose: To prospectively quantify changes in anterior segment morphology after laser peripheral iridotomy(LPI) using the Van Herick grade of peripheral anterior chamber depth, A-scan ultrasonography, gonioscopy and ultrasound biomiscroscopy(UBM) in eyes with occludable angles, which were diagnosed in physical examination without acute attack. To research effect of LPI to eyes with occludable angles.Methods: The eyes with occludable angles were diagnosed in the health examination in Sir Run Run Shaw hospital during March 2006 to February 2007. The eyes were examed by the Van Herick grade of limbal anterior chamber depth, A-scan ultrasonography, gonioscopy and ultrasound biomiscroscopy(UBM) before and after performed the LPI. The results of pre- and post LPI, including the anterior chamber depth, the angle open distance and the degree of the anterior chamber angle, were statistical analysed.Result: There were 34 patients who were diagnosed occludable-angle eyes and performed LPI during March 2006 to February 2007. Fifteen patients (thirty eyes)were examed. Ten patients of them were bilateral occludable-angle eyes, and five patients were unilateral occludable-angle eye. There were 25 occludable-angle eyes, 78.1% of all eyes.The peripheral anterior chamber depth and gonioscopy grading of the chamber angle significantly increased in all 4 quadrants(p<0.001). The morphology of the anterior chambers was wider showed by the UBM figures. AOD500 and the anterior chamber angle allsignificantly increased after LPI(p<0.001).The anterior chamber depth examed by A-scan ultrasonography did not change significantly.9 eyes of the occludable-angle eyes were still occludable-angle eyes, 36% of the 25 occludable-angle eyes. The gonioscopy grading of the chamber angle didn't significantly increased in 4 quadrants. The peripheral anterior chamber depth(p<0.001), AOD500 and the anterior chamber angle (p<0.05)all significantly increased after LPI.Conclusions: In occludable-angle eyes, LPI produced a significant widening of the anterior chamber angle without deepening the central anterior chamber. UBM could be used to observe the fine morphplogy after the LPI directly, measure the parameters and watch some change which was not able to watch by the gonioscopy.