Abstract: Objective To compare the degree of angle closure and the difference of quantitative biological parameters in different quadrants in primary angle closure suspect (PACS) eye. Design Prospective case series. Participants 112 cases of PACS. Methods Only one eye of each subject that met the inclusion criteria was selected for analysis. Firstly, gonioscopy was performed in selected eyes and the angle status of the superior, inferior, nasal and temporal quadrants was recorded and compared. Then the selected eyes were examined by anterior segment optical coherence tomography (AS-OCT), and the biological parameters of anterior chamber angle at nasal and temporal sides were measured and compared. Main Outcome Measures The angle configuration at four quadrants, angle open distance at 500 μm (AOD500), trabecular iris area at 500 μm (TISA500), iris curvature (Icurv), iris thickness at 2000 μm (IT2000) at the nasal and temporal sides. Results The percentage of angle closure in the superior quadrant (98.21%) was higher than that in the inferior quadrant (75.89%), nasal quadrant (64.29%) and temporal quadrant (76.79%) (χ2= 40.225, P<0.001). The width of the temporal angle AOD500(0.12±0.06) mm was larger than that of the nasal side (0.11±0.06) mm (P<0.001), the area of the temporal angle TISA500(0.07±0.03) mm2 was larger than that of the nasal side (0.06±0.03) mm2 (P=0.008), the Icurv in the temporal angle (0.41±0.11) mm was larger than that of the nasal side (0.37±0.1) mm (P=0.001) and the IT2000 of temporal angle (0.46±0.07) mm was smaller than that of nasal angle (0.49±0.06) mm (P<0.001). Conclusion The configuration of anterior chamber angle in different quadrants of the same eye is different in PACS eyes. The superior angle was more closed than angle in other quadrants, the iris of temporal angle was thinner than that of nasal angle, and the temporal angle is wider than the nasal one. （Ophthalmol CHN, 2020, 29: 361-364）

Key words: primary angle closure suspect, anterior chamber angle, iris