Glaucoma is one of the three major blindness-causing diseases in ophthalmology and is a group of diseases characterized by optic papillary atrophy and depression, visual field defects and vision loss. Pathologically increased intraocular pressure and insufficient blood supply to the optic nerve are the main causes of its development. Because of its irreversible nature, it is more aggressive than other ophthalmic diseases and is known as the “invisible vision killer”. Glaucoma is divided into primary and secondary; open-angle and closed-angle; and congenital. The treatment for each type of glaucoma is different. However, the principle of treatment for both surgery and medication is to lower the intraocular pressure and protect the optic nerve. The damage to the optic nerve and visual field that has been caused cannot be cured or repaired. The only factors we can control in the treatment of glaucoma are to lower and control the IOP and to protect the residual visual function. All treatment revolves around this. In summary, treatment of glaucoma can only be a protective control treatment, but it is irreversible and incurable for the damage already caused to the optic nerve and to the vision. Therefore, glaucoma must be detected, diagnosed and treated early to avoid irreversible consequences.