Sudden blurring of vision one year after cataract surgery requires a return to the hospital as soon as possible for a review to find the specific cause before treatment. The causes of this symptom include posterior cataract, retinal detachment, and vitreous hemorrhage. Cataract patients usually need to be treated by surgery, the principle of which is to replace the cloudy lens with a transparent IOL in order to restore vision. Sudden vision loss one year after surgery may be caused by posterior cataract, which can be restored by laser treatment to cut the cloudy posterior capsule. Sudden vision loss one year after surgery may also be caused by retinal detachment, which usually requires surgical treatment to reset the retina to restore vision. If it is caused by vitreous blood accumulation, medication can be used to promote the absorption of the blood accumulation, such as urokinase intravitreal injection, and if it is not absorbed, it may need to be removed by surgery. The medication should be used according to the doctor’s prescription. Sudden blurring of vision one year after cataract surgery should be promptly sought medical advice, under the guidance of the doctor to clarify the cause and treatment.