Related articles: Night Blindness
Definition
Night blindness means difficulty in seeing at night or in poor lighting conditions; this can lead to problems moving in the dark or driving at night. Night blindness can also be associated with a delayed visual adaptation in switching from bright to dark environments, and vice versa. The vision remains normal during the day.
Night blindness occurs when the retina loses its sensitivity due to a malfunction of the photoreceptors (in particular, rods) and other retinal cells. This visual disorder is often associated with aging, but can also occur in the event of cataracts, glaucoma, myopia and vitamin A deficiency. If night blindness occurs in young people it could be a first sign of retinitis pigmentosa, a degenerative retinal disorder which can causes a progressive loss of sight.
The symptom of "night blindness" is also known as nictalopia; a similar condition is instead called emeralopia and consists in the difficulty of twilight vision.
Possible Causes * of Night Blindness
- Cataract
- Keratoconus
- Age-related macular degeneration
- Glaucoma
- Myopia
- Optic neuritis
- Retinitis pigmentosa
- Retinoblastoma
- Diabetic retinopathy
