To evaluate post-miosis changes in the anterior chamber structures in various angle-closure glaucomas (ACG). Totally 14 eyes of primary chronic angle-closure glaucoma (PCACG), 12 eyes of lens-induced secondary chronic angle-closure glaucoma (LSACG) and 14 healthy eyes were recruited. After miosis, for PCACG group, intraocular pressure (IOP) and anterior chamber depth (ACD) changed not significantly, while anterior chamber angle widened significantly. LSACG group showed a significant increase in IOP, decrease in ACD, and narrowing in anterior chamber angle. Healthy eyes showed significant decreases in IOP and anterior chamber parameters. Thus, miosis could widen the anterior chamber angle of patients with PCACG, while increase the narrowing of anterior chamber angle and IOP of patients with LSACG. We should pay attention to the distinction between PCACG and LSACG patients and the proper administration of pilocarpine in the treatment of patients with chronic ACG.