Abstract: Myopia is generally considered a protective factor for primary angle-closure glaucoma (PACG). However, with the change of environmental factors and the increase of near visual activity, the prevalence of myopia increased significantly, but the incidence of PACG did not decrease accordingly. Myopia, as a protective effect on PACG, actually refers to axial myopia rather than refractive myopia. The non pupillary block mechanism is more common in patients with high myopia and angle closure than in the general angle closure population. The angle closure in PACG patients with long axial length is mainly caused by non pupillary block mechanisms, especially the high pleated iris configuration. The increase in lens thickness and forward movement form a shallow anterior chamber, narrowing the width of the anterior chamber and flattening the corneal edge leading to angle narrower. Changes in iris area, thickness, curvature, as well as ciliary and neurovascular factors also play a certain promoting role in the process of angle closure in axial myopia. (Int Rev Ophthalmol, 2025, 49:  81-87)

Key words: primary angle-closure glaucoma, myopia, axial length, anterior chamber depth