If there is a significant decrease in vision within a short period of time, it is usually seen in fundus diseases. Common diseases include retinal artery obstruction, retinal vein obstruction, optic neuritis, ischemic optic neuropathy, vitreous hemorrhage, retinal detachment, glaucoma, uveitis, and so on. Therefore, once this situation occurs, it is necessary to go to the hospital as soon as possible to do fundus examination, only to clarify the specific causes of the disease, in order to know how to go to the treatment. Fundus diseases are complex, timely to the fundus disease specialist clinic, a clear examination, clear the cause of the disease and then carry out active treatment.