There are many causes of sudden night blindness. Night blindness refers to blurry vision or even complete inability to see in low-light conditions such as nighttime, possibly even leading to difficulties in movement.

Night blindness can be categorized into congenital, acquired, and temporary types. Congenital night blindness is mostly related to genetic factors, where the patient is born with a deficiency in synthesizing rhodopsin, leading to night blindness. Temporary night blindness is often due to a lack of Vitamin A in the diet, or due to some digestive system diseases that affect the absorption of Vitamin A. Acquired night blindness is usually caused by diseases of the retina or the eye itself.

Therefore, if sudden night blindness occurs, it is recommended to go to a reputable hospital's ophthalmology department for comprehensive examinations such as visual acuity, intraocular pressure, slit lamp, dilated fundus examination, and if necessary, further tests like fundus fluorescein angiography to identify the cause and provide targeted treatment.