(Nyctanopia; Nyctalopia; Day Sight; Nocturnal Amblyopia)
DefinitionNight blindness means having difficulty seeing in the dark or in low light. One of the most common issues with night blindness is difficulty driving in the evening or at night.
|The Retina of the Eye|
|Copyright © Nucleus Medical Media, Inc.|
CausesNight blindness is caused by a disorder of the cells in the retina that are responsible for vision in dim light (cones). There may be several common causes:
- Lack of vitamin A, which can cause a disorder of the retina
- Cataracts , which are cloudy areas in the lens of the eye
- Some forms of retinal degeneration, such as retinitis pigmentosa
- Certain medications
- Birth defects
Risk FactorsFactors that may increase your chance of night blindness include:
- Age—Elderly people are more likely to have cataracts.
- Dietary deficiencies—Not getting adequate amounts of vitamin A, which come from green leafy vegetables, eggs, and whole milk products.Vitamin A deficiency is very rare in the US, but still occurs in certain less developed countries.
- Disorders that affect the ability of the body to absorb vitamin A:
- Liver disorders
- Surgery on the pancreas or liver
- Intestinal conditions
- Bowel surgery for obesity
- Trouble adjusting from low levels of light to high levels of light
SymptomsSymptoms are difficulty or inability to see in low light or darkness. While driving, this may also occur a few seconds after the bright headlights of an oncoming car have passed.
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