General Description
Night blindness is a term used to describe disorders in which people
see normally during the day but see poorly at night or during low-light
conditions. Their eyes often have trouble adjusting to glare or
to sudden changes in light levels. The condition does not involve
true blindness (in spite of its name), even at night. Night blindness
is usually caused by abnormal function of the light-gathering cells
in the eye, which may be a sign of a nutritional deficiency or may
be a symptom of a more serious eye disorder such as retinitis pigmentosa.
Night blindness is commonly seen in people with conditions that
interfere with the absorption of vitamin A or zinc, such as alcoholism,
liver disease, or intestinal disorders.
Nutritional/lifestyle considerations
Because night blindness is a common symptom of vitamin A deficiency,
people suffering from the condition should make sure they get
a good daily supply of vitamin A or beta-carotene, which the body
converts into the vitamin. In numerous studies, symptoms of night
blindness improved when patients were given vitamin A supplements.1-7
Adequate zinc intake is also important for people suffering night
blindness because zinc-dependent enzymes play key roles in vitamin
A metabolism and transport.8 Herbalists have
long recommended bilberries and bilberry extracts for people with
night blindness; however, recent placebo-controlled studies failed
to show any improvement in night vision in subjects given bilberry
supplements.9,10 |
