Night blindness is also called nyctalopia. It is a type of vision impairment. People with nyctalopia blindness experience poor vision at night or in dimly lit environments. When lighting is dim, the eye must adapt so that it can be able to see.
Although the term “night blindness” implies that you can’t see at night, this isn’t the case. 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.
What are the symptoms?
Night blindness itself is a symptom of an underlying eye condition that results in vision impairment while in dim lighting. Night blindness could prevent someone from being able to see stars at night, or obstacles in a dark room.
The nature of other symptoms that accompany night blindness will depend on the underlying condition and may include:
- Eye pain.
- Blurry, or cloudy vision.
- Sensitivity to light.
- Difficulty seeing into the distance.
What Causes Night Blindness?
A number of eye conditions can cause night blindness, including:
- Usher syndrome: This is a genetic condition that affects both hearing and vision
- Age: As we age, our pupils don’t dilate in the dark as much as they should, thus reducing the amount of light that enters our eyes.
- Glaucoma: This refers to a group of eye conditions where damage to the optic nerve, which connects the eye to the brain, causes pressure in the eye. This may impair vision, which can be permanent.
- Cataracts: This occur when the lens of the eye becomes cloudy. It 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, or retinol deficiency: This 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.
- Retinitis pigmentosa: 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.
- Sun exposure: Without proper eye protection, sun exposure can temporarily impair night vision for up to two days. Wearing sunglasses that protect against UVA and UVB rays will prevent temporary blindness due to sun exposure.
- Diabetic retinopathy : This is a condition that occurs as a result of damage to the blood vessels of the retina in people who have diabetes. Diabetic retinopathy can develop if you have type 1 or 2 diabetes and a long history of uncontrolled high blood sugar levels.
- Abetalipoproteinemia (ABL) : This is an inherited condition that prevents the body from completely absorbing certain dietary fats. Without treatment, it can cause vitamin deficiencies that may have long-term effects on your health. Dietary fats and the vitamins they contain are important for the growth and development of many of your body’s organs and tissues, including the brain.
How is Night Blindness Treated?
Treatment will depend upon its cause. Your eye doctor will take a detailed medical history and examine your eyes to diagnose night blindness. You may also need to give a blood sample. Blood testing can measure your vitamin A and glucose levels.
Night blindness caused by near-sightedness, cataracts, or vitamin A deficiency is treatable. Corrective lenses, such as eyeglasses or contacts, can improve nearsighted vision both during the day and at night.
Let your doctor know if you still have trouble seeing in dim light even with corrective lenses. Also treatment may be as simple as getting a new eyeglass prescription or switching glaucoma medications, or it may require surgery if the night blindness is caused by cataracts.
If a retinal disease is discovered, the treatment will depend on the type of the disease and will require additional investigation by a retina specialist.
How Can I Prevent Night Blindness?
You can’t prevent night blindness which comes as a result of birth defects or genetic conditions, such as Usher syndrome. You can, however, properly monitor your blood sugar levels and eat a balanced diet to make night blindness less likely.
Eat foods rich in antioxidant vitamins and minerals, which may help prevent cataracts. Also, choose foods that contain high levels of vitamin A to reduce your risk of blindness. Certain orange-colored foods are excellent sources of vitamin A, including:
- Collard greens