Fundus examination is a necessary option for the diagnosis of glaucoma, but it is not the whole story. Whether glaucoma can be diagnosed depends on whether the intraocular pressure is elevated and whether the optic nerve in the fundus has been damaged. This part needs to be combined with visual field examination, optic nerve fiber layer analysis, etc. to determine whether there is nerve damage. The most common manifestation of fundus examination in glaucoma is an increased cup-to-disc ratio, but a large cup-to-disc ratio is not an absolute diagnostic criterion for glaucoma, as there are many normal people with a large cup-to-disc ratio. In addition to a larger cup-to-disc ratio, there will be bleeding along the disc rim as well as narrowing and shallowing, which will require an experienced physician to diagnose based on a combination of medial and lateral disc rims as well as superior and inferior ratios.