What is Night Blindness?
Night blindness, also known as nyctalopia, is a condition that means your eyes are unable to adapt to low light conditions. Night blindness usually occurs as a result of problems with your rod cells, although there are actually several causes of night blindness.
- Night blindness, or nyctalopia, is when the eye is unable to adapt to low light conditions, such as at night. Night blindness is not a condition, but the result of an existing eye problem.
- When the lighting is low, the eye must adapt. Although night blindness negatively affects a person's ability to see in dim light, it does not cause complete blindness. This can create problems seeing traffic signs while driving at night. It may also take longer than usual for the eye to adjust when changing from light to dark setting.
- Night blindness is a symptom of certain underlying conditions, which can have several causes. This article will discuss the symptoms, potential causes, and treatments for night blindness.
Causes of Night Blindness
- Some eye problems can lead to night blindness, such as:
- blurred visionblurred vision when looking at distant objects
- cataracts or clouding of the lens
- retinitis pigmentosa, which occurs when dark pigment builds up in your retina and creates tunnel vision
- Usher's syndrome, a genetic illness that affects both hearing and vision
- Older people are at greater risk of developing cataracts. They are therefore more likely to suffer from night blindness due to cataracts than children or young adults.
- In rare cases in the United States or other parts of the world where diets may vary, a vitamin A deficiency can also lead to night blindness.
- Vitamin A, also called retinol, plays a role in transforming nerve impulses into pictures in the retina. The retina is an area sensitive to light behind the eye.
- People with pancreatic insufficiencies, such as people 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 an increased risk of night blindness.
- People who have high blood glucose levels or diabetes also have a higher risk of developing eye diseases, such as cataracts.
Diagnosis of Night Blindness
The doctor's decision to make a diagnosis will depend on your age and any other symptoms or results of the physical exam. Possible tests may include:
- Night blindness can only be diagnosed with a comprehensive eye exam.
- Your ophthalmologist will ask you questions about your medical history and perform a series of tests to identify signs of eye disease or vision disturbances.
- Many ophthalmologists use the Pelli-Robson Contrast Sensitivity Chart to detect signs of night blindness. This graphic contains many rows of letters in different shades of gray, on a white background.
- During this test, you will be asked to identify the letters on the card. As your eyes move downward from the graph, the letters appear in lighter shades of gray because the contrast with the white background is reduced.
- Some ophthalmologists may also require a blood test to determine your vitamin A and glucose levels.
- Vitamin A deficiency can directly cause night blindness, while abnormal glucose levels can lead to an eye disease that can affect your retinal health and vision - and often lead to night blindness.
Treatment of Night Blindness
Night blindness treatment depends on the cause. Treatment may be as simple as getting a new prescription for glasses or changing your glaucoma medication, or it may require surgery if cataracts cause night blindness.
If you have a retinal disease, treatment will depend on the type of disease and will require further investigation by a retinal specialist.
When to visit a Doctor
If you have difficulty seeing while driving at night - or if you cannot see at all, or if you are sitting in a dimly lit restaurant and can barely see, you may have night blindness. See your healthcare professional immediately, as night blindness can be a symptom of serious illness.
Prevention Night Blindness
You cannot prevent night blindness caused by birth defects or genetic diseases, such as Usher syndrome. However, you can properly monitor your blood sugar and eat a balanced diet to reduce the risk of night blindness.
Eat foods rich in antioxidants, vitamins, and minerals, which can help prevent cataracts. Also, choose foods that contain high levels of vitamin A to lower your risk of night blindness.
Some orange-colored foods are significant sources of vitamin A, including:
- cantaloupe
- sweet potatoes
- carrots
- pumpkins
- butternut squash
- mangoes
Vitamin A is also present in:
- spinach
- green cabbage
- milk
- eggs
