出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/04/29 16:21 UTC 版)
Nyctalopia (from Greek νύκτ-, nykt- "night"; and αλαός, alaos "blindness") is a condition making it difficult or impossible to see in relatively low light. It is a symptom of several eye diseases. Night blindness may exist from birth, or be caused by injury or malnutrition (for example, a lack of vitamin A). It can be described as insufficient adaptation to darkness.