The eyes do not see clearly at a distance and do not see clearly up close, often seen in keratoconus, glaucoma, cataract, retinal and optic nerve diseases. The cornea is an important refractive medium. Decreased transparency of the cornea due to inflammation, trauma, etc. will affect vision accordingly. Glaucoma can damage the optic nerve due to high intraocular pressure, which also affects vision. Cataracts mainly refer to the clouding of the lens, which is also an important refractive medium, and the clouding of the lens can lead to vision loss. Retinopathy, such as retinal hemorrhage, degeneration, and detachment, can seriously affect visual function. Optic neuropathy can also damage the optic nerve, resulting in vision loss. It is recommended that the patient should consult a doctor in time to identify the cause of vision loss and then treat the symptoms.