What deficiency causes night blindness?

Night blindness is primarily a visual disorder caused by a deficiency of vitamin A in the body. Vitamin A is an essential nutrient for maintaining normal retinal function and plays a key role in the synthesis of rhodopsin, the light-sensitive pigment in the retina. When the body lacks vitamin A, the production of rhodopsin in the retina decreases, leading to reduced vision in low-light conditions—commonly known as "night blindness." To treat night blindness, it is recommended to increase dietary intake of sufficient vitamin A by consuming foods rich in this nutrient, such as animal liver, fish liver oil, carrots, spinach, and others. If dietary adjustments are insufficient, vitamin A supplements may be taken under medical supervision. Maintaining healthy lifestyle habits, such as avoiding prolonged work or screen time in dim lighting, can also help alleviate symptoms of night blindness. If symptoms persist or worsen, prompt medical evaluation is advised to rule out other underlying causes.