An ultrasound biomicroscopic study of the anterior segment in Indian eyes with primary angle-closure glaucoma

Purpose: To evaluate the presence of plateau iris in eyes with primary angle-closure glaucoma (PACG) after laser peripheral iridotomy by gonioscopy and ultrasound biomicroscopy and to evaluate the pathogenesis of this condition by comparing the UBM parameters of these eyes with those in normal subjects. Patients and Methods: This prospective study was carried out in the Glaucoma clinic of a tertiary eye care center. A detailed clinical examination including applanation tonometry, indentation gonioscopy with a Sussman four-mirror gonioscope, and ultrasound biomicroscopic examination in one randomly selected eye of 55 patients (55 eyes) with PACG who had undergone laser peripheral iridotomy and 22 normal subjects (22 eyes). Results: Among the PACG eyes, 40% (22/55) had an open angle (angle opening distance > 130 microns) and 60% (33/55) eyes had a narrow angle (angle opening distance less than or equal to 130 microns). A large anteriorly placed ciliary process with a narrow ciliary sulcus was found in 9 of the 22 eyes with open angle (40.9%), and 22 of the 33 eyes with narrow angles (66.66%). Trabecular ciliary process distance was significantly larger in the eyes with open angles compared with those with narrow angles (P = 0.001). Conclusions: Plateau iris was common in the clinic population studied. Anteriorly directed ciliary processes were seen both in eyes with plateau iris as well as in eyes with PACG that had deep anterior chambers after iridotomy.