Peripheral Anterior Synechia Reduce Extent of Angle Widening After Laser Peripheral Iridotomy in Eyes With Primary Angle Closure

Purpose: To quantify the effect of laser peripheral iridotomy (LPI) on angle widening in primary angle closure with and without peripheral anterior synechia (PAS). Patients and Methods: Prospective hospital-based study of 44 consecutive patients (69 eyes) with primary angle closure. Comprehensive ophthalmic examination and ultrasound biomicroscopy were performed at enrollment and 2 weeks following LPI. The following angle parameters: angle opening distance, trabecular-iris angle, and angle recess area were obtained. On the basis of the presence of PAS, angle quadrants were divided into 3 groups: group A comprised quadrants in PAS-negative eyes; group B, the unaffected quadrants in PAS-positive eyes; and group C, the quadrants with PAS in PAS-positive eyes. Correlation between PAS and angle width was determined and changes in angle parameters following LPI were compared between groups. Results: Sixty-six eyes of 42 patients (31 eyes with PAS) were available for analysis. Groups A, B, and C provided 140, 66, and 58 quadrants, respectively, for analysis. There was a moderate negative correlation between angle width changes (angle opening distance, trabecular-iris angle, angle recess area) after LPI and PAS extent at baseline (r=-0.46 to-0.39; P