Night Blindness | Health Notes at WWSM | Health Information at WWSM

Night Blindness

Also indexed as: Nyctalopia

Driving during the darker hours of the day can be difficult when you have night blindness. According to research or other evidence, the following self-care steps may help improve your vision in low light:

Get a nutritional check-up
Visit a knowledgeable professional to find out whether your night blindness is caused by a vitamin A or zinc deficiency

Deal with the deficiency
Supplement with vitamin A and zinc to correct those deficiencies that may lead to night blindness; see your doctor to determine recommended amounts and duration of treatment

These recommendations are not comprehensive and are not intended to replace the advice of your doctor or chemist. Continue reading the full night blindness article for more in-depth, fully-referenced information on medicines, vitamins, herbs, and dietary and lifestyle changes that may be helpful.

About night blindness

People with night blindness (also called impaired dark adaptation) see poorly in the darkness but see normally when adequate amounts of light are present. The condition does not actually involve true blindness, even at night.

Product ratings for night blindness

Science Ratings	Nutritional Supplements	Herbs
	Beta-carotene Vitamin A Zinc (for deficiency)
	Iron (for deficiency)
		Bilberry
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For a herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

What are the symptoms?

Symptoms include difficulty seeing when driving in the evening or at night, poor vision in reduced light, and feeling that the eyes take longer to “adjust” to seeing in the dark.

Other therapies

Therapy includes management of any underlying medical condition.

Vitamins that may be helpful

Night blindness may be an early sign of vitamin A deficiency. Such a deficiency may result from diets low in animal foods (the main source of vitamin A), such as eggs, dairy products, organ meats, and some fish. Low intake of fruits and vegetables containing beta-carotene, which the body converts into vitamin A, may also contribute to a vitamin A deficiency. Doctors often recommend 10,000 to 25,000 IU of vitamin A per day to correct a deficiency. Beta-carotene is less effective at correcting vitamin A deficiency than is vitamin A itself, because it is not absorbed as well and is only slowly converted by the body into vitamin A.

Dietary zinc deficiency is common, and a lack of zinc may reduce the activity of retinol dehydrogenase, an enzyme needed to help vitamin A work in the eye. Zinc helps night blindness in people who are zinc-deficient;¹ therefore, many physicians suggest 15 to 30 mg of zinc per day to support healthy vision. Because long-term zinc supplementation may reduce copper levels, 1 to 2 mg of copper per day (depending on the amount of zinc used) is usually recommended for people who are supplementing with zinc for more than a few weeks.

In a study of women in Nepal, where there is a high prevalence of iron and riboflavin deficiencies, supplementation with 30 mg per day of iron and 6 mg per day of riboflavin for six weeks enhanced the effectiveness of vitamin A in the treatment of night blindness.² It is not known whether these nutrients would be helpful for night blindness in people who are not deficient.

Are there any side effects or interactions?
Refer to the individual supplement for information about any side effects or interactions.

Herbs that may be helpful

Bilberry, a close relative of the blueberry, is high in flavonoids known as anthocyanosides. Anthocyanosides speed the regeneration of rhodopsin, the purple pigment that is used by the rods in the eye for night vision.³ Supplementation with bilberry has been shown in early studies to improve dark adaptation in people with poor night vision.⁴ ⁵ However, two newer studies found no effect of bilberry on night vision in healthy people.⁶ ⁷ Bilberry extract standardised to contain 25% anthocyanosides may be taken in capsule or tablet form. Doctors typically recommend 240 to 480 mg per day.

Are there any side effects or interactions?
Refer to the individual herb for information about any side effects or interactions.

References
(To view, roll mouse over the "References" heading; to hide, click on the heading)

Learn more about Healthnotes, the company.

Learn more about the authors of Healthnotes.

The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires September 2008.