Vitamin A deficiency also contributes to development of night blindness because of the nutrient’s importance in maintaining the health of the eye’s retina. One study reported in Journal of Nutrition (October 2004) effectively used tests detecting night blindness in pregnant women to determine whether mothers-to-be lacked vitamin A considered crucial for healthy development of their babies.
Retinitis Pigmentosa is characterized by night blindness and black dotting of the fundus. The Optic Nerve becomes pale white, called Optic atrophy.
Types of Night Blindness
- Congenital Stationary Night Blindness: This type of night blindness, present at birth, can have varying causes often related to inherited disorders.
- Progressive Night Blindness: As implied by the name, progressive night blindness continues to worsen. Causes can include factors such as vitamin A deficiency, disease, and toxic effects of drugs including quinine used to treat malaria and other conditions.
- Night Blindness as Complication of Obesity Surgery: Individuals who undergo obesity surgery altering the way the body absorbs food can develop night blindness, primarily because nutrients such as vitamin A may be lacking if patients fail to use nutritional supplements following surgery.
Night blindness is due to a disorder of the cells in the retina that are responsible for vision in dim light. It has many causes,
- Lack of vitamin A, which can cause a disorder of the retina and make the eyes very dry
- Cataracts, which are cloudy areas in the lens of the eye
- Some forms of retinal degeneration, like retinitis pigmentosa
- Trouble adjusting from low levels of light to high levels of light
- Certain medications
- Birth defects
Some risk factors for night blindness include:
- Age: older people are more likely to have cataracts
- Diet: people who don’t eat enough sources of vitamin A, such as 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
Symptoms 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.
Associated symptoms include:
Treatment for night blindness will depend upon its cause . Treatments generally include:
- Taking vitamin A supplements
- Removal of the cataracts.
- Eating a diet with adequate amounts of Vitamin A may help prevent night blindness.