A significant decrease in vision may be due to recent overexertion of the eyes, which requires rest, but if the decrease is significant in a short period of time, it may also be due to refractive errors, cataracts, glaucoma, or fundus disorders. 1. Refractive error: Refractive error can lead to loss of vision, and may also lead to strabismus, which is the main way to cause vision loss in the clinic. 2. Cataract: Cataract patients suffer from vision loss due to decreased transparency or color change of the lens, which may cause rapid vision loss in a short period of time. 3. Glaucoma: As the second most common blinding eye disease in the world, glaucoma is characterized by optic nerve atrophy and visual field defects, which can cause rapid vision loss. 4. Fundus diseases: Patients with fundus diseases such as retinopathy, optic neuropathy, choroidopathy, etc. can suffer rapid vision loss in a short period of time due to direct damage to the fundus. It is recommended that patients with significant vision loss should consult a doctor in a timely manner to assess their condition and follow the doctor’s instructions for treatment.