[Observation of the chamber angle in primary angle-closure glaucoma with an ultrasound biomicroscope].

We observed the chamber angle in 47 eyes of 29 patients with primary angle-closure glaucoma using ultrasound biomicroscopy in dark and illuminated conditions. All observations were made before surgical intervention and without any drugs affecting pupillary reaction. Ultrasound biomicroscopy was repeated following laser iridotomy in 23 of the eyes. Out of 115 angle locations examined where no synechiae had been found by pressure gonioscopy, appositional angle closure was seen at 65 locations (57%) in 33 eyes (70%) in dark conditions. At 30 angle locations in 18 eyes, the appositional closure began in the vicinity of Schwalbe's line. After iridotomy, appositional closure was not observed even in dark conditions. Ultrasound biomicroscopy in dark conditions seems to be a promising procedure to visualize appositional angle closure in eyes with a narrow angle.