Night blindness, impaired vision in dim light and in the dark, due to impaired function of certain specialized vision cells.
The condition of being unable to see in bad light.
Inability to see well in a faint light or at night. This condition occurs in retinitis pigmentosa and choroidoretinitis; it may also be due to vitamin A deficiency. Smoking tobacco may impair the ability to see at night. Hypoxia associated with being above sea level in an aircraft will also decrease night vision.