• Night Blindness

    (Nyctanopia; Nyctalopia; Day Sight; Nocturnal Amblyopia)

    Definition

    Night blindness is difficulty seeing in the dark or in low light. One of the most common issues with night blindness is difficulty driving in the evening or at night.
    The Retina of the Eye
    AR00025 96472 1
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    Causes

    Night blindness is caused by disorders or conditions that affect the cells in the retina that are responsible for vision in dim light (cones). Examples include:
    • Common vision disorders, such as difficulty seeing or focusing on distant objects (nearsightedness)
    • Cataracts, which are cloudy areas in the lens of the eye
    • Some forms of retinal degeneration, such as retinitis pigmentosa
    • Posterior uveitis
    • Certain medications, such as those used to treat glaucoma
    • Vitamin A deficiency
    • Birth defects affecting the retina

    Risk Factors

    Age is the most common factor that contributes to night blindness. Many eye conditions develop as people get older. Other factors that may increase the chance of night blindness include:
    • Trouble adjusting from low levels of light to high levels of light
    • History of eye disorders, such as cataracts or glaucoma
    • Diabetes (contributes to eye disorders)
    • Family history of eye disorders
    • Genetic mutations that contribute to eye disorders
    • Not getting adequate amounts of vitamin A, which come from green leafy vegetables, eggs, and whole milk products. Vitamin A deficiency is rare in the United States, but still occurs in certain less developed countries.
    • Disorders that affect the ability of the body to absorb vitamin A:
      • Liver or pancreatic disorders
      • Intestinal conditions
      • Gastric bypass surgery for obesity

    Symptoms

    Symptoms are difficulty or inability to see in low light or darkness, even with glasses or contact lenses. While driving, this may also occur a few seconds after the bright headlights of an oncoming car have passed.

    Diagnosis

    Your doctor will ask about your symptoms and medical history. A complete eye exam will be done. A blood test can be used to test the amount of vitamin A in your blood.

    Treatment

    Treatment depends on the cause of night blindness. Options may include:
    • Taking vitamin A supplements
    • Having cataracts removed
    • Taking medications to treat eye conditions
    • Using low-vision aids and making lifestyle adjustments
    Night blindness may require taking extra safety precautions when necessary. This may mean avoiding driving in the evening or at night.

    Prevention

    To help reduce your chance of night blindness:
    • Follow treatment plans for chronic conditions that may contribute to night blindness
    • Have regular eye exams as advised by your eye doctor
    • Eating a diet with adequate amounts of vitamin A

    RESOURCES

    American Optometric Association http://www.aoa.org

    Eye Smart—American Academpy of Ophthalmology http://www.eyesmart.org

    CANADIAN RESOURCES

    Canadian Ophthalmological Society http://www.cos-sco.ca

    Health Canada http://www.hc-sc.gc.ca

    References

    Cataract in adults. EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/dmp~AN~T116240/Cataracts-in-adults. Updated August 31, 2016. Accessed September 29, 2016.

    Glaucoma and driving. Glaucoma Research Foundation website. Available at: http://www.glaucoma.org/treatment/glaucoma-and-driving.php. Updated April 1, 2013. Accessed December 9, 2015.

    Night blindness. Cleveland Clinic website. Available at: http://my.clevelandclinic.org/services/cole-eye/diseases-conditions/hic-night-blindness. Updated March 18, 2015. Accessed December 9, 2015.

    Open-angle glaucoma. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T114157/Open-angle-glaucoma. Updated June 2, 2016. Accessed September 29, 2016.

    Retinitis pigmentosa. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T116916/Retinitis-pigmentosa. Updated September 30, 2014. Accessed December 9, 2015.

    Vitamin A. Office of Dietary Supplements website. Available at: https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional. Updated June 5, 2013. Accessed December 9, 2015.

    What is low vision? American Academy of Ophthalmology Eye Smart website. Available at: http://www.geteyesmart.org/eyesmart/diseases/low-vision.cfm. Accessed December 9, 2015.

    Revision Information

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