Night blindness, or nyctalopia, is where the eye is unable to adapt to low-light conditions, such as at nighttime. Night blindness itself is not a condition but the result of an existing eye disorder.
When lighting is dim, the eye must adapt. Although night blindness adversely affects a person's ability to see in dim light, it does not cause complete blindness. It may create problems seeing road signs while driving at night. It may also take longer time than usual for the eye to adapt when going from light to dark settings.
Night blindness is a symptom of some underlying conditions, which may have several causes. This article will discuss symptoms, potential causes, and treatments of night blindness.
Night blindness is a symptom of an underlying eye condition that results in vision impairment while in dim lighting.
For example, night blindness could prevent someone from being able to see stars at night, or obstacles in a dark room.
To identify night blindness, the American Academy of Ophthalmology suggests that people consider the following questions:
- Is moving around the house in dim light a challenge?
- Is driving at night increasingly difficult?
- Is it tricky to recognize faces in dim light?
- Does it take an abnormally long time to adjust to a light room after being in the dark?
- Does it take a long time to see in a darkened room after being in the light?
Other symptoms may also occur with night blindness. The nature of these symptoms will depend on the underlying cause but may include:
- eye pain
- blurry, or cloudy vision
- sensitivity to light
- difficulty seeing into the distance
Night blindness is the result of one of several conditions, many of which are treatable. Conditions can include:
Cataracts occur when the lens of the eye becomes cloudy. This often happens when proteins in the lens break down, usually due to aging. Clouding of the lens can impair vision, including in dim lighting.
People with nearsightedness, which doctors call myopia, are unable to see objects in the distance accurately. This occurs when the eye grows too long and no longer focuses light correctly.
Vitamin A deficiency
Vitamin A, or retinol, is an essential nutrient for vision. For example, it makes up a protein that absorbs light in the retina and supports eye functioning. Vitamin A deficiencies can have a serious impact on vision.
This is a group of rare eye diseases that damage the retina. It is a genetic disorder that results in difficulty seeing in low light.
Treatment for night blindness will vary depending on the cause.
Treatment may include wearing specific types of glasses or contact lenses, which can help to support correct vision.
Wearing sunglasses can also protect the eye from ultraviolet light, which can cause further eye damage.
When the cause is a lack of vitamin A, treatment involves adding more Vitamin A to the diet. Good sources of vitamin A include:
- fortified cereals
- fortified milk
- orange and yellow vegetables and fruits
- cod liver oil
- dark, leafy green vegetables
Eye surgery may be necessary in more severe cases. For example, LASIK is a type of surgery that changes the shape of the cornea to improve vision. Other types of surgery may aim to remove a cataract from the eye or to release pressure in the eye for treatment of glaucoma.
In some cases, night blindness may not be treatable. Retinitis pigmentosa currently has no effective treatments, although certain eye devices and therapy services may improve symptoms and quality of life.
It may be helpful to take precautions to lower some of the risks that night blindness can cause. This might mean not driving at night, or avoiding having to navigate or move around in the dark wherever possible.
The outlook for night blindness depends on the cause.
The cause will have a range of straightforward treatments in many cases. This can be as simple as new glasses or contact lenses or adapting to a different diet. More severe cases may require surgery.
Effective treatment can significantly improve vision at night, as well as other symptoms of the underlying condition causing it.