Abstract: Objective  To quantitatively evaluate the long-term changes in anterior segment morphology by using of ultrasound biomicroscopy (UBM) after laser peripheral iridotomy (LPI) in eyes with primary angle closure suspect (PACS). Design Prospective case series. Participants 55 PACS consecutive patients in Handan Eye Hospital, Hebei were enrolled. Methods Routine ophthalmic tests and UBM examination were performed at presentation and 12 months after LPI. Main Outcome Measures The parameters of anterior chamber angle in UBM images. Results AOD500, AOD750, TIA500, TIA750, ARA500, and ARA750 were significantly widen at 12 months after LPI than that at presentation in eyes with PACS (all P<0.001). The value of AOD, TIA and ARA after LPI were at least 1 time (1.08-1.14 times) wider than that of before LPI, and the parameters at 750 ?滋m anterior to the sclera spur were more significantly wide than its 500 ?滋m counterpart.  Conclusion  LPI can significantly widen the peripheral anterior angle in eyes with PACS and this effectiveness tends to be sustained at least 1 year after LPI. Parameters at 750 ?滋m anterior to the sclera spur were more sensitive in evaluating the peripheral anterior angle. (Ophthalmol CHN, 2013, 22: 244-248)

Key words: laser peripheral iridotomy, ultrasound biomicroscopy, primary angle closure suspect