Primary glaucoma is clinically divided into two major categories: angle-closure glaucoma and open-angle glaucoma. The difference between them is that angle-closure glaucoma is due to a pre-existing abnormal configuration of the iris, leading to a mechanical blockage of the anterior chamber angle by peripheral iris tissue, which obstructs the outflow of aqueous humor, thus causing an increase in intraocular pressure. In contrast, open-angle glaucoma has a normal appearance of the anterior chamber angle, which remains open, and its increase in intraocular pressure is due to a pathology in the trabecular meshwork’s aqueous humor outflow system, increasing the resistance to aqueous outflow. Currently, the ratio of primary angle-closure glaucoma to primary open-angle glaucoma is about 3:1, making it the most common type of glaucoma in China.