The concept that glaucomatous optic atrophy, optic disc pitting and glaucomatous visual field loss are often attributed to elevated intraocular pressure has caused doubts. This is because some patients have these changes even without high intraocular pressure. This condition was first described by von Graefe (1857), and has since attracted the attention of ophthalmologists, who have given it various names. Although some doctors believe that similar changes may be caused by carotid artery calcification, alcoholism, pituitary tumors, etc., after long-term observation, many patients with these changes cannot find the above reasons. For this type of eye disease that cannot find a definite cause, with intraocular pressure within the normal range and glaucomatous optic disc atrophy, pitting and visual field damage, it is classified as low-tension glaucoma (hereinafter referred to as LTG). In modern literature, many are normal-tension glaucoma. The incidence of LTG in the population is about 0.15%, accounting for 18-20% of all open-angle glaucoma.