- nyctalopia, night blindness, moon blindness - inability to see clearly in dim light; due to a deficiency of vitamin A or to a retinal disorder
--1 is a kind of visual impairment, visual defect, vision defect, visual disorder; avitaminosis, hypovitaminosis
- moon blindness, mooneye - recurrent eye inflammation in horses; sometimes resulting in blindness
--2 is a kind of animal disease