To describe the distribution and characteristics of peripheral anterior synechiae (PAS) in patients with primary angle-closure glaucoma (PACG).

Retrospective case study. A total of 285 PACG patients (406 eyes) diagnosed in the Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University from January 2017 to August 2019 were included. They were 102 males and 183 females, with a median age of 67 years old (range, 21 to 95 years old). The PAS range was detected by gonioscopy examination, and the frequency distribution of PAS at 12 clock points was counted by clockwise. The PAS distribution at the middle point of PAS with continuous distribution and ≤6 clock points was assessed.

In all cases, PAS of the right eye was concentrated at 11:00 to 4:00 regions [range, 62.0% (129/208) to 78.8% (164/208)]. PAS of the left eye was concentrated at 7:00 to 1:00 regions [range, 50.0% (99/198) to 75.8% (150/198)]. When the PAS range of the atrial angle was ≤6 clock regions, it was mainly at 12:00 to 3:00 [range, 58.3% (74/127) to 67.7% (86/127)] in the right eye and at 10:00 to 12:00 [range, 54.8% (68/124) to 66.1% (82/124)] in the left eye. Among 121 cases (242 eyes) with both eyes involved, the PAS region was at 11:00 to 5:00 [range, 52.1% (63/121) to 79.3% (96/121)] in the right eye and at 8:00 to 1:00 [range, 50.4% (61/121) to 76.9% (93/121)] in the left eye. When the PAS range of the atrial angle was ≤6 clock regions, it was mainly at 12:00 to 4:00 [range, 53.2% (41/77) to 71.4% (55/77)] in the right eye and at 10:00 to 12:00 [range, 50.6% (39/77) to 64.9% (50/77)] in the left eye. In all cases, there were 171 cases of right eyes and 175 cases of left eyes with continuous angle PAS. The central PAS clock position of the right eye was mainly at 11:00 to 3:00 [range, 15.2% (26/171) to 24.0% (41/171)], and that of the left eye was mainly at 8:00 to 12:00 [range, 15.4% (27/175) to 20.6% (36/175)]. Among cases with both eyes involved, there were 98 cases of right eyes and 104 cases of left eyes with continuous angle PAS. The clock distribution of the middle position of the right eye angle PAS was concentrated at 11:00 to 3:00 [range, 17.3% (17/98) to 26.5% (26/98)], and that of the left eye was concentrated at 8:00 to 12:00 [range, 13.5% (14/104) to 20.2% (21/104)].

The PAS of PACG patients is mainly located in the upper and nasal sides, and the closer to the temporal side, the smaller the PAS frequency, showing a gradual downward trend. The PAS distribution of binocular angles is of obvious mirror symmetry.(Chin J Ophthalmol, 2021, 57: 666-671)

Glaucoma, angle-closure; Iris diseases; Peripheral anterior synechiae