Night
Blindness: Night blindness (nyctalopia) is 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 cannot see at night, this is not the case.
You may just have more difficulty seeing and/or driving in darkness.
Some types of night blindness are treatable, and
others are not. Consult 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.
Causes: A number of eye
conditions can cause night blindness, including:
- nearsightedness:
blurred vision when looking at faraway objects
- cataracts:
a clouding of the eye’s lens
- retinitis pigmentosa:
when dark pigment collects in your retina,
creating tunnel vision
- Usher syndrome:
a genetic condition that affects both
hearing and vision
Older adults have a greater risk of developing
cataracts. Seniors are therefore more likely to suffer from night blindness
than children or young adults.
In rare cases, 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 diseases of the liver or pancreas
sometimes cannot absorb large amounts of vitamin A. So, they are at greater
risk for developing night blindness, according to Boston’s Beth Israel
Deaconess Medical Center (BIDMC).
Symptoms: The sole
symptom of night blindness is difficulty seeing in the dark. You are more
likely to suffer from night blindness when transitioning from a bright
environment to an area of low light. You are likely to experience poor vision
when driving, due to the intermittent brightness of headlights and streetlights
on the road.
Treatment: Your eye doctor
will take a detailed medical history and examine your eyes in order to diagnose
night blindness. You may also be asked 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.
Treating Catracts
Clouded portions of your eye’s lens are called
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.
Treating 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 the developed world do not suffer from vitamin A deficiency because they
have access to proper nutrition.
Prevention: Night blindness that is the result of birth defects or genetic conditions, such as Usher syndrome,
cannot be prevented. 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. Orange-colored
foods are excellent sources of vitamin A, including:
- cantaloupes
- sweet
potatoes
- carrots
- pumpkins
- butternut
squash
- mangoes
Spinach, collard greens, milk, and eggs also
contain vitamin A.
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