Night blindness (impaired dark adaptation) is the experience of reduced night vision. It typically causes people to not be able to see well in the darkness but be able to see without problem when it is not dark. This condition, unless accompanied by other eye pathology, is not true blindness; even at nighttime, the eye is not "blind" but occurs because the rods of the photoreceptor cells which are needed for dim light are not functioning correctly.
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Can vary on an individual basis for each patient. Symptoms include weak vision in dim light, difficulty seeing during night driving, and slow vision adaption between bright and dim light conditions. Only your doctor can provide adequate diagnosis of any signs or symptoms and whether they are indeed night blindness symptoms.
Causes & Related Conditions
The following medical conditions are some of the possible causes of night blindness. There are likely to be other possible causes, so ask your doctor regarding your symptoms.
- Retinitis pigmentosa
- Macular Degeneration
- Rod-Cone Dystrophy
- Vitamin A deficiency
- Malabsorption - if it affects vitamin A absorption
- Celiac disease
- Cystic fibrosis
- Bile duct obstruction
- Cirrhosis of the liver
- Severe short-sightedness (myopia)
- Congenital night vision disorder
Self Help - Diet & Nutrition
- Certain nutrients such as bilberry, lutein, ginkgo biloba, zeaxanthin, vitamin A, and other vitamins and minerals may help night blindness and preserve vision.
- See recommended nutrients.
- See our recommendations for diet / lifestyle.
- Vegetables. Vitamin A rich vegetables such as dark green vegetables like spinach, collards, and orange and yellow vegetables such as carrots and sweet potatoes.
- Increase your visibility - clean your headlights
- Slow down. That way, you give yourself more time to react to any unexpected hazards.
- Always wear sunglasses outside, especially on bright days. Blue and green eyed people are particularly sensitive to potential sun-induced damage, so the use of eye protection is paramount. Amber and grey lenses are the most effective protection against UVA/UVB and blue light.
- Get prescription glasses for driving at night if needed (see your eye doctor to determine if they would be helpful).
- Look to the right. Look at the roadway's edge to the right to help you avoid the glare of oncoming headlights.
- Leave the driving till tomorrow. Drive only during the day. Even good lighting conditions at night such as found in a big city can be troublesome to someone with night blindness.
An early indicator of a deficiency in vitamin A may be night blindness. A primary source of vitamin A is from animal sources, so diets such as a vegan diet without eggs, dairy, some fish, and/or organ meats may result in deficiency of vitamin A. The body makes vitamin A from beta-carotene found in yellow/orange vegetables and fruits, so if those are also not part of the diet, the risk is greater. Health care providers may recommend vitamin A (10,000 - 25,000 IU) daily in order to overcome deficiency. Beta-carotene can also be taken to reverse a deficiency, but it is not as effective as taking vitamin A directly. This is because beta-carotene is absorbed slowly by the body and slowly converted to vitamin A.
Vitamin A palmitate is the best form of supplemental vitamin A. 15,000 IU is often the recommended daily dosage (check with your doctor or nutritionist). Note that vitamin A is contra-indicated for those suffering from Stargardt's disease.
Night blindness may also be the result of a zinc deficiency which reduces the activity of an enzyme that helps the body produce vitamin A (retinol dehydrogenase). Research has shown that taking a zinc supplement is helpful. Healthcare providers often recommend 15 - 30 mg of zinc daily for vision. At the same time long-term supplementation with zinc may lower copper levels, so 1 - 2 mg of copper daily is recommended to be taken with zinc for extended use. In general, the recommended supplement ratio is 15:1 zinc to copper. Consult your medical professional for correct dosage if you are supplementing with zinc.
Bilberry (a blueberry relative) grows in northern Europe and North America in the wild. It is rich in flavonoids, specifically bilberry which is rich in anthocyanosides, the elements in plants that provide color. These natural chemicals are potent antioxidants that, among other benefits, enhance the creation of the purple pigment (rhodopsin) that is used by the rods in the back of the eye to assist with night vision. Early research has shown that bilberry supplementation improves the speed of adapting to darkness for people who have poor night vision.
Zinc supplementation might potentiate the effect of vitamin A in restoring night vision in pregnant Nepalese women, Am J Clin Nutr June 2001 vol. 73 no. 6 1045-1051
Also see research on night blindness.