Acquired causes:
1. Cataracts: people with cataracts often have difficulty reading, driving a car — especially at night — and seeing facial expressions.
2. Myopia: night blindness can be a sign of untreated myopia.
3. Use of certain drugs: some glaucoma medications can cause constriction of the pupils, which can make it difficult to see at night.
4. Vitamin A deficiency: Night blindness is one of the first signs of vitamin A deficiency, which is commonly associated with malnutrition. The vitamin deficiency often develops in malnourished children who are too young to recognize a problem with their night vision or report a vision problem.
Congenital causes:
1. Congenital stationary night blindness with or without myopia: This stands for a group of genetically heterogeneous disorders. One type of congenital stationary night blindness affects only males; females are carriers of the gene but do not have symptoms.
2. Retinitis pigmentosa: This eye disease is caused by a number of genetic defects that result in damage to the retina. Affected persons may have decreased vision at night or in low light. They may also have problems with central and peripheral vision. Symptoms may detected in childhood but often become apparent in adulthood.
3. Usher syndrome: This syndrome is characterized by hearing loss and retinitis pigmentosa, which, as noted above, can cause night blindness.