Facts About Night Blindness

Night blindness, or nyctalopia, is he inability to see well at night or in low lighting conditions like
at a restaurant. This is a symptom of a problem with usually the retina, the tissue that lines the back of
the eye. If you are nearsighted, you may also experience trouble seeing at night but this is not due to an
issue with the retina, it is an optical problem.

To understand this, I want to go over what happens to your eyes in different lighting conditions.
When it is dark, your pupil gets larger so that more light can come into the eye so you are able to see.
The light that enters the eye falls onto the retina which has cells called rods and cones. The cone cells
help you see color and the rods help you see in the dark. If the rods aren’t working properly due to
disease or injury, you won’t see well in the dark.

Causes for Night Blindness

  1. Cataracts– Cataracts make the natural lens inside the eye cloudy which limits the amount of light
    that reaches the retina in the back of the eye. They can cause you to need more light to see and
    can cause trouble with glare. Cataract surgery can fix this problem.
  2. Nearsightedness- Being nearsighted makes it hard to see well at a distance in the dark,
    especially if your glasses or contacts are not the right strength. If this is the problem, all you
    need is an updated prescription to fix this.
  3. Medications- Certain medications can change the size of the pupil making it more difficult for
    light to enter the eye. Some medications can also slow down how the pupil reacts when moving
    from bright to dim surroundings. This means that it takes longer for your eyes to adjust to
    darker rooms.
  4. Vitamin A deficiency- Vitamin A is a precursor of the photopigment called rhodopsin which is
    found in the rods which, as we discussed earlier, is essential for seeing at night. This can be
    reversed by adding foods rich in vitamin A such as carrots, dairy, cantaloupes, butternut squash,
    spinach, and eggs.
  5. Retinitis Pigmentosa- This is a hereditary condition that causes progressive night blindness. The
    retina deteriorates which in return causes difficulty seeing at night. This disease also affects
    peripheral vision and causes problems seeing even in normal lighting conditions. Unfortunately
    there is no treatment to stop or cure retinitis pigmentosa at this time but research is ongoing.

Treatment for Night Blindness

Treatment for night blindness of course depends on the cause. It may just involve updating your glasses prescription or changing medications. If cataracts are the cause, it may require surgery. Getting regular eye exams, wearing sunglasses to protect your eyes from UV damage, and getting exercise are all good preventative measures you can take to help protect your eyes. If you have trouble driving at night or can’t see well in dim conditions, see your eye doctor to make sure that the eyes are healthy and free of disease.

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Dr. Thirion

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