What causes night blindness? 3 possible conditions
Night blindness is also called “nyctalopia.” It’s a type of vision impairment. People with night blindness experience poor vision at night or in dimly lit environments. Although the term “night blindness” implies that you can’t see at night, this isn’t the... Read more
Night blindness is also called “nyctalopia.” It’s a type of vision impairment. People with night blindness experience poor vision at night or in dimly lit environments. Although the term “night blindness” implies that you can’t see at night, this isn’t the case. You may just have more difficulty seeing or driving in darkness.
Some types of night blindness are treatable, and other types aren’t. See your doctor to determine the underlying cause of your vision impairment. Once you know the cause of the problem, you can take steps to correct your vision.
What Are the Symptoms of Night Blindness?
The sole symptom of night blindness is difficulty seeing in the dark. You’re more likely to experience night blindness when your eyes transition from a bright environment to an area of low light, such as when you leave a sunny sidewalk to enter a dimly lit restaurant. You’re likely to experience poor vision when driving due to the intermittent brightness of headlights and streetlights on the road.
What Causes Night Blindness?
A number of eye conditions can cause night blindness, including:
- nearsightedness, or blurred vision when looking at faraway objects
- cataracts, or clouding of the eye’s lens
- retinitis pigmentosa, which occurs when dark pigment collects in your retina and creates tunnel vision
- Usher syndrome, which is a genetic condition that affects both hearing and vision
Older adults have a greater risk of developing cataracts. Seniors are therefore more likely to have night blindness due to cataracts than children or young adults.
In rare cases in the United States or in other parts of the world where nutritional diets may vary, vitamin A deficiency can also lead to night blindness. Vitamin A, also called retinol, plays a role in transforming nerve impulses into images in the retina. The retina is a light-sensitive area in the back of your eye.
Patients who have pancreatic insufficiency, such as individuals with cystic fibrosis, have difficulty absorbing fat and are at a greater risk of having vitamin A deficiency because vitamin A is fat-soluble. This puts them at greater risk for developing night blindness.
People who have high blood glucose, or sugar, levels or diabetes also have a higher risk of developing eye diseases, such as cataracts.
What Are the Treatment Options for Night Blindness?
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 nearsightedness, 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.
Clouded portions of your eye’s lens are known as cataracts. Cataracts can be removed through surgery. Your surgeon will replace your cloudy lens with a clear, artificial lens. Your night blindness will improve significantly after surgery if cataracts are the underlying cause.
Vitamin A Deficiency
If your vitamin A levels are low, your doctor might recommend vitamin supplements. Take the supplements exactly as directed. Most people in developed nations don’t have vitamin A deficiency because they have access to proper nutrition.
Genetic conditions that cause night blindness, such as retinitis pigmentosa, aren’t treatable. The genetic defect that causes pigment to build up in the retina doesn’t respond to corrective lenses or surgery. People who have this form of night blindness should avoid driving at night.
How Can I Prevent Night Blindness?
You can’t prevent night blindness that’s the 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 night blindness. Certain orange-colored foods are excellent sources of vitamin A, including:
- sweet potatoes
- butternut squash
Vitamin A is also in:
- collard greens
What Is the Long-Term Outlook?
If you have night blindness, you should take precautions to keep yourself and others safe. Refrain from driving at night as much as possible until the cause of your night blindness is determined and, if possible, treated.
Arrange to do your driving during the day, or secure a ride from a friend, family member, or taxi service if you need to go somewhere at night. Wearing sunglasses or a brimmed hat can also help reduce glare when you’re in a brightly lit environment, which can ease the transition into a darker environment.
- Facts about Usher syndrome. (2010, October). Retrieved from https://nei.nih.gov/health/ushers/ushers#a
- Mayo Clinic Staff. (2013, July 30). Cataracts. Retrieved from http://www.mayoclinic.org/diseases-conditions/cataracts/basics/definition/con-20015113
- Night blindness. (2014, December). Retrieved from http://www.mountsinai.org/patient-care/health-library/diseases-and-conditions/night-blindness
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