Loss of vision at night may be related to refractive error, night blindness and cataract. 1. Refractive error: Blurred vision is caused when parallel light rays from both eyes are unable to focus on the retinal plane at the same time due to improper use of the eyes, or heredity, or prolonged over-exertion of the eyes. It is possible that the vision of eyes in poor light is more blurred compared to normal people. 2. Night blindness: Due to low vitamin A content in food or zinc deficiency, retinal rod cells are malnourished and the eyes are less sensitive to low light, resulting in reduced vision at night. 3. Cataract: It may be caused by the aging of eye tissues, tumors, etc., causing the lens to become cloudy, which will affect the vision. Coupled with poor lighting at night, vision loss can occur. When vision loss occurs at night, it is recommended to consult a doctor in a timely manner, follow the doctor’s instructions and then further relevant examinations, with the help of the doctor to clarify the cause, and targeted treatment or therapy.