Night blindness is a common symptom in ophthalmology, referring to a condition where patients cannot see clearly in dim environments. Night blindness can be caused by various reasons, among which vitamin A deficiency night blindness occurs due to the patient's long-term picky eating or malnutrition, leading to insufficient intake of vitamin A. Vitamin A is an essential raw material for the synthesis of photosensitive substances in the retina, and its deficiency can lead to night blindness. Night blindness caused by retinal pigment degeneration, malnutrition of rod cells, and late-stage glaucoma does not involve a lack of nutritional elements in the patient's body. Instead, it results from damage to the rod cells in the retina or the nerve fiber layer, which prevents them from sensing light stimuli in dark environments.